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Male Offspring (male + offspring)
Selected AbstractsThe influence of natural variations in maternal care on play fighting in the ratDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2008Carine I. Parent Abstract Naturally occurring variations in maternal care in the rat influence the sensitivity of offspring to stress in adulthood. The offspring of mothers that show lower levels of pup licking/grooming (i.e., low-LG mothers) demonstrate enhanced responses to stress and increased anxiety compared to those of high-LG mothers. Low-LG offspring are also more sensitive to the influence of environmental enrichment than high-LG offspring. This study examined play fighting in the juvenile offspring of high-LG and low-LG dams in a multiple-play partners housing environment. Male offspring from low-LG dams demonstrated a significantly higher frequency of pouncing, pinning and aggressive social grooming than did high-LG males and high-LG and low-LG females. Consistent with earlier reports, male pups engaged in more play fighting than did females and maternal care was associated with differences in play fighting but only in males. Lower levels of stimulation in the form of LG from the dam during perinatal development may thus increase sensitivity for the stimulating effects of play behavior in periadolescence, in part explaining the increased solicitation of play fighting through increased pouncing in the male offspring of the low-LG mothers. These findings identify a possible influence of variations in maternal care on play fighting and suggest that maternal care in the perinatal period influence social interactions during periadolescence. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 767,776, 2008 [source] Antiandrogenic effects of dibutyl phthalate and its metabolite, monobutyl phthalate, in ratsCONGENITAL ANOMALIES, Issue 4 2002Makoto Ema ABSTRACT, Developmental toxicity following administration of dibutyl phthalate (DBF) and its major metabolite, monobutyl phthalate (MBuP), by gavage was determined in Wistar rats. DBF on days 0,8 of pregnancy induced an increase in the incidence of preimplantation loss at 1250 mg/kg and higher and postimplantation loss at 750 mg/kg and higher. MBuP on days 0,8 of pregnancy produced an increase in the incidence of pre-and postimplantation loss at 1000 mg/kg. DBF on days 7,15 of pregnancy caused an increase in the incidence of fetuses with malformations at 750 mg/kg. MBuP on days 7,15 of pregnancy produced an increased incidence of fetuses with malformations at 500 mg/kg and higher. DBF on days 15,17 of pregnancy resulted in a decrease in the anogenital distance (AGD) of male fetuses and increase in the incidence of fetuses with undescended testes at 500 mg/kg and higher. MBuP on days 15,17 of pregnancy caused a decreased male AGD and increased incidence of fetuses with undescended testes at 250 mg/kg and higher. No effect of DBF and MBuP on the AGD was found in female offspring. The spectrum of fetal malformations, dependence of gestational days of treatment on the manifestation of teratogenicity, and alterations in development of the male reproductive system observed after administration of DBF were in good agreement with those observed after administration of MBuP. These findings suggest that MBuP may be responsible for the induction of developmental toxic effects of DBP. The doses that produced a decrease in the AGD and undescended testes in male offspring were lower than those producing maternal toxicity, fetal malformations after administration during major organogenesis, and embryonic loss. The male reproductive system may be more susceptible than other organ systems to DBP and MBuP toxicity after maternal exposure. [source] Disruption of brain development in male rats exposed prenatally to 5-bromo-2,-deoxyuridineCONGENITAL ANOMALIES, Issue 4 2001Makiko Kuwagata ABSTRACT, Sprague-Dawley rats were treated intraperitoneally with 5-bromo-2,-deoxyuridine (BrdU) at 0,12.5 or 50 mg/kg/day on days 9 through 15 of gestation to evaluate the effects on development of the brain of offspring. Prenatal exposure to BrdU induced abnormal development of the brain; dilatation of the lateral ventricles in male offspring in the postnatal period. The ratio of the length of the longitudinal fissure to that of the cerebral cortex decreased in a dose-dependent manner in the embryonic period and thereafter. In 14-week-old male offspring exposed prenatally to BrdU at 50 mg/kg, the cortex layer of the cerebrum was thinner than that of the controls. Masculine sexual behavior was markedly impaired and the volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) was decreased in the 50 mg/kg group as compared with the controls. These results demonstrate that prenatal exposure to BrdU affected the development of the brain hi the prenatal and postnatal stages and reduced the volume of SDN-POA after puberty, resulting in a disruption of reproductive ability in male rats. [source] The influence of natural variations in maternal care on play fighting in the ratDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2008Carine I. Parent Abstract Naturally occurring variations in maternal care in the rat influence the sensitivity of offspring to stress in adulthood. The offspring of mothers that show lower levels of pup licking/grooming (i.e., low-LG mothers) demonstrate enhanced responses to stress and increased anxiety compared to those of high-LG mothers. Low-LG offspring are also more sensitive to the influence of environmental enrichment than high-LG offspring. This study examined play fighting in the juvenile offspring of high-LG and low-LG dams in a multiple-play partners housing environment. Male offspring from low-LG dams demonstrated a significantly higher frequency of pouncing, pinning and aggressive social grooming than did high-LG males and high-LG and low-LG females. Consistent with earlier reports, male pups engaged in more play fighting than did females and maternal care was associated with differences in play fighting but only in males. Lower levels of stimulation in the form of LG from the dam during perinatal development may thus increase sensitivity for the stimulating effects of play behavior in periadolescence, in part explaining the increased solicitation of play fighting through increased pouncing in the male offspring of the low-LG mothers. These findings identify a possible influence of variations in maternal care on play fighting and suggest that maternal care in the perinatal period influence social interactions during periadolescence. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 767,776, 2008 [source] Maternal blood glucose in diabetic pregnancies and cognitive performance in offspring in young adulthood: a Danish cohort studyDIABETIC MEDICINE, Issue 7 2010G. L. Nielsen Diabet. Med. 27, 786,790 (2010) Abstract Aims, Maternal diabetes is a known risk factor for perinatal complications, but there are little data on consequences for long-term intellectual outcome in offspring. We assess cognitive performance in military conscripts according to maternal blood glucose levels during pregnancy. Methods, We identified a cohort of 60 Danish male offspring of insulin-treated diabetic mothers born between 1976 and 1984 and followed this cohort to military conscription. From medical records, we extracted data on all available values of maternal blood glucose categorized as fasting and non-fasting and by day in pregnancy, together with maternal White class, smoking habits and socio-economic status. The main outcome was cognitive performance at conscription measured with a validated intelligence test. The association between maternal blood glucose level and cognitive performance was assessed by multivariate linear regression and a fitted fractional polynomial. Results, Median fasting blood glucose values in the second half of pregnancy was negatively associated with cognitive scores at conscription [adjusted coefficient ,1.7; 95% confidence interval (CI) ,3.0; ,0.4]. Restriction to only first-born sibling slightly strengthened the association (coefficient ,1.9; 95% CI ,3.3; ,0.5), but after exclusion of two pregnancies with the blood glucose > 10 mmol/l the association became insignificant (coefficient ,0.6; 95% CI ,2.6; 1.4). Conclusions, Maternal blood glucose level during diabetic pregnancy is negatively associated with cognitive performance in offspring at military conscription. In pregnancies with fasting blood glucose levels below 10 mmol/l, the association is weak and considered to be without clinical relevance. [source] Adaptive Offspring Sex Ratio Depends on Male Tail Length in the GuppyETHOLOGY, Issue 11 2006Kenji Karino A biased sex ratio in a brood is considered to be an adaptive strategy under certain circumstances. For example, if the expected reproductive success of one sex is greater than that of the other, parents should produce more offspring of the former sex than the latter. A previous study has documented that in the guppy, Poecilia reticulata, the female offspring of males possessing proportionally longer tails exhibit smaller body sizes and show decreased reproductive outputs than those of males having shorter tails. On the other hand, the total lengths of the male offspring of the long-tailed males are larger because of their longer tails; consequently, they exhibit greater sexual attractiveness to females. Therefore, it has been hypothesized that this asymmetry in the expected reproductive success between the male and female offspring of long-tailed males may result in a biased sex ratio that is dependent on the tail lengths of their fathers. This hypothesis was tested in the present study. The results showed that the females that mated with long-tailed males produced more male offspring than those that mated with short-tailed males. Logistic regression analysis showed that the ratio of tail length to the standard length of the fathers is a determinant factor of the sex of their offspring. These results suggest that the manipulation of the offspring sex ratios by parents enhances the overall fitness of the offspring. [source] The Association Between Male Offspring Aggression and Paternal and Maternal Behavior of Peromyscus MiceETHOLOGY, Issue 10 2003Janet K. Bester-Meredith Parents influence offspring aggression through genetic and non-genetic mechanisms, although the latter are less well understood. To examine potential non-genetic effects of parents on offspring, we cross-fostered the highly aggressive and biparental California mouse (Peromyscus californicus) and the less aggressive, less parental white-footed mouse (Peromyscus leucopus). In-fostered animals within each species were used as controls. We examined associations between the foster parents' behavior and aggression of the fostered male offspring in resident,intruder (R,I) and neutral arena aggression tests. When both species and fostering groups were combined, R,I aggression of offspring was positively associated with paternal time spent retrieving pups. In contrast, aggression in a neutral arena was negatively associated with a composite score of maternal behavior. We discuss how our findings regarding paternal retrievals may explain previously reported effects of cross-fostering on male aggression. [source] Prenatal stress reduces postnatal neurogenesis in rats selectively bred for high, but not low, anxiety: possible key role of placental 11,-hydroxysteroid dehydrogenase type 2EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009P. J. Lucassen Abstract Prenatal stress (PS) produces persistent abnormalities in anxiety-related behaviors, stress responsivity, susceptibility to psychopathology and hippocampal changes in adult offspring. The hippocampus shows a remarkable degree of structural plasticity, notably in response to stress and glucocorticoids. We hypothesized that PS would differentially affect hippocampal neurogenesis in rats selectively bred for genetic differences in anxiety-related behaviors and stress responsivity. Pregnant dams of high anxiety-related behavior (HAB) and low anxiety-related behavior (LAB) strains were stressed between days 5 and 20 of pregnancy. The survival of newly generated hippocampal cells was found to be significantly lower in 43-day-old HAB than in LAB male offspring of unstressed pregnancies. PS further reduced newly generated cell numbers only in HAB rats, and this was paralleled by a reduction in doublecortin-positive cell numbers, indicative of reduced neurogenesis. As maternal plasma corticosterone levels during PS were similar in both strains, we examined placental 11,-hydroxysteroid dehydrogenase type 2 (11,-HSD2), which catalyses rapid inactivation of maternal corticosterone to inert 11-dehydrocorticosterone and thus serves as a physiological ,barrier' to maternal glucocorticoids. PS significantly increased placental 11,-HSD2 activity in LAB, but not HAB, rats. We conclude that PS differentially affects the number of surviving newly generated cells and neurogenesis in HAB and LAB rats. The high sensitivity of hippocampal neurogenesis to PS in HAB rats is paralleled by a failure to increase placental 11,-HSD2 activity after stress rather than by different maternal corticosterone responses. Hence, stress-induced placental 11,-HSD2 expression may be critical in protecting the fetal brain from maternal stress-induced effects on adult neurogenesis. [source] Postnatal handling reverses social anxiety in serotonin receptor 1A knockout miceGENES, BRAIN AND BEHAVIOR, Issue 1 2010C. Zanettini Mice lacking the serotonin receptor 1A (Htr1a knockout, Htr1aKO) show increased innate and conditioned anxiety. This phenotype depends on functional receptor activity during the third through fifth weeks of life and thus appears to be the result of long-term changes in brain function as a consequence of an early deficit in serotonin signaling. To evaluate whether this phenotype can be influenced by early environmental factors, we subjected Htr1a knockout mice to postnatal handling, a procedure known to reduce anxiety-like behavior and stress responses in adulthood. Offspring of heterozygous Htr1a knockout mice were separated from their mother and exposed 15 min each day from postnatal day 1 (PD1) to PD14 to clean bedding. Control animals were left undisturbed. Maternal behavior was observed during the first 13 days of life. Adult male offspring were tested in the open field, social approach and resident,intruder tests and assessed for corticosterone response to restraint stress. Knockout mice showed increased anxiety in the open field and in the social approach test as well as an enhanced corticosterone response to stress. However, while no effect of postnatal handling was seen in wild-type mice, handling reduced anxiety-like behavior in the social interaction test and the corticosterone response to stress in knockout mice. These findings extend the anxiety phenotype of Htr1aKO mice to include social anxiety and demonstrate that this phenotype can be moderated by early environmental factors. [source] A mixture of seven antiandrogens induces reproductive malformations in ratsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2008Cynthia V. Rider Summary To date, regulatory agencies have not considered conducting cumulative risk assessments for mixtures of chemicals with diverse mechanisms of toxicity because it is assumed that the chemicals will act independently and the individual chemical doses are not additive. However, this assumption is not supported by new research addressing the joint effects of chemicals that disrupt reproductive tract development in the male rat by disrupting the androgen signalling pathway via diverse mechanisms of toxicity [i.e. androgen receptor (AR) antagonism in the reproductive tract vs. inhibition of androgen synthesis in the foetal testis]. In this study, pregnant rats were exposed to four dilutions of a mixture containing vinclozolin, procymidone, linuron, prochloraz, benzyl butyl phthalate, dibutyl phthalate and diethylhexyl phthalate during the period of sexual differentiation and male offspring were assessed for effects on hormone sensitive endpoints including: anogenital distance, infant areolae retention and reproductive tract tissue weights and malformations. The ratio of the chemicals in the mixture was based upon each chemical's ED50 for inducing reproductive tract malformations (hypospadias or epididymal agenesis). The observed responses from the mixture were compared with predicted responses generated with a toxic equivalency approach and models of dose addition, response addition or integrated addition. As hypothesized, we found that the mixture of chemicals that alter the androgen signalling pathway via diverse mechanisms disrupted male rat reproductive tract differentiation and induced malformations in a cumulative, dose-additive manner. The toxic equivalency and dose addition models provided the best fit to observed responses even though the chemicals do not act via a common cellular mechanism of action. The current regulatory framework for conducting cumulative risk assessments needs to consider the results, including those presented herein, which indicate that chemicals that disrupt foetal tissues during sexual differentiation act in a cumulative, dose-additive manner irrespective of the specific cellular mechanism of toxicity. [source] Reproductive function in male rats after brief in utero exposure to diethylstilboestrolINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2000G. H. G. Behrens Long-term effects of brief in utero exposure to diethylstilboestrol (DES) during a foetal period known to be critical for gonadal development were evaluated. Rats were exposed to DES (100 ,g/kg body-weight) from day 17 to 19 of pregnancy. All of the DES-treated pregnant rats (11/11) ate parts or whole of their offspring during the first day after birth (p=0.03). Surviving male offspring were examined on day 63 post-partum. DES induced a reduction in weight of the testis (p=0.06) and ventral prostate (p=0.07), even after this short exposure. DES tended to reduce the number of Sertoli cells (p=0.13). Our findings indicate that even a short in utero exposure of rats to DES during a critical period for gonadal development results in cannibalism and reduced testis and ventral prostate weight. [source] Levels of soluble HLA-G in amniotic fluid are related to the sex of the offspringINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2003P. M. Emmer Summary Although HLA-G is thought to play a modulatory role in the immune system, its function and expression require to be elucidated. We analysed soluble HLA-G levels in mid-trimester amniotic fluid (n = 64) from uncomplicated pregnancies. We found a decrease in soluble HLA-G levels for female offspring as compared to male offspring (P < 0.007). This may be a consequence of the immuno-modulatory capacity of HLA-G. [source] Molecular and cytogenetic paternity testing of a male offspring of a hinnyJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 6 2006C.J. Zhao Summary An alleged male foal of a female mule, whose sire and grandparents were unknown, was identified for its pedigree. Parentage testing was conducted by comparing polymorphism of 12 microsatellite DNA sites and mitochondrial D-loop sequences of the male foal and the female mule. Both the sequence analysis of species-specific DNA fragments and a cytogenetic analysis were performed to identify the species of the foal and its parents. The results showed that the alleged female mule is actually a hinny, and the male foal, which possesses 62 chromosomes, qualifies as an offspring of the female hinny and a jack donkey. [source] Sex-related effects of maternal egg investment on offspring in relation to carotenoid availability in the great titJOURNAL OF ANIMAL ECOLOGY, Issue 1 2008Anne Berthouly Summary 1Maternal carotenoids in the egg yolk have been hypothesized to promote maturation of the immune system and protect against free radical damages. Depending on availability, mothers may thus influence offspring quality by depositing variable amounts of carotenoids into the eggs. Sex allocation theory predicts that in good quality environments, females should invest into offspring of the sex that will provide larger fitness return, generally males. 2In a field experiment we tested whether female great tits bias their investment towards males when carotenoid availability is increased, and whether male offspring of carotenoid-supplemented mothers show higher body condition. We partially cross-fostered hatchlings to disentangle maternal effects from post-hatching effects, and manipulated hen flea Ceratophyllus gallinae infestation to investigate the relationship between carotenoid availability and resistance to ectoparasites. 3As predicted, we found that carotenoid-supplemented mothers produced males that were heavier than their sisters at hatching, while the reverse was true for control mothers. This suggests that carotenoid availability during egg production affects male and female hatchlings differentially, possibly via a differential allocation to male and female eggs. 4A main effect of maternal supplementation became visible 14 days after hatching when nestlings hatched from eggs laid by carotenoid-supplemented mothers had gained significantly more mass than control nestlings. Independently of the carotenoid treatment, fleas impaired mass gain of nestlings during the first 9 days in large broods only and reduced tarsus length of male nestlings at an age of 14 days, suggesting a cost to mount a defence against parasites. 5Overall, our results suggest that pre-laying availability of carotenoids affects nestling condition in a sex-specific way with potentially longer-lasting effects on offspring fitness. [source] Causes and consequences of adaptive seasonal sex ratio variation in house sparrowsJOURNAL OF ANIMAL ECOLOGY, Issue 5 2006ARILD HUSBY Summary 1Here we examine how sex ratio variation in house sparrow broods interacts with other demographic traits and parental characteristics to improve the understanding of adaptive significance and demographic effects on variation in sex ratio. 2The sex ratio in complete broods did not deviate significantly from parity (54·9% males). 3There was sex-specific seasonal variation in the probability of recruitment. Male nestlings that hatched late in the breeding season had larger probability of surviving than early hatched males. 4An adaptive adjustment of sex ratio should favour production of an excess of males late in the breeding season. Accordingly, the proportion of male offspring increased throughout the breeding season. 5A significant nonlinear relationship was present between sex ratio and age of the female. However, there was no relationship between parental phenotype and standardized hatch day that could explain the observed seasonal change in sex ratio. 6The sex-specific number of offspring recruited by a pair to subsequent generations was closely related to the brood sex ratio. 7These results indicate an adaptive adjustment of sex ratio to seasonal variation in environmental conditions that affects the offspring fitness of the two sexes differently. Our results also suggest that such a sex ratio variation can strongly influence the demography and structural composition of small passerine populations. [source] Reproduction of the ambrosia beetle, Xyleborus pfeili (Ratzeburg) (Col., Scolytidae), on semi-artificial dietJOURNAL OF APPLIED ENTOMOLOGY, Issue 9 2002T. Mizuno Unmated females produced only male offspring, while broods that originated from fertilized females had strongly female-biased sex ratios. Thus, the reproductive process of X. pfeili is arrhenotokous parthenogenesis. Oviposition took place over a long time, as eggs were present in the tunnels throughout the experiments (up to 40 days after inoculation). Total length of a gallery system and number of offspring per tube were positively correlated. Pupation and eclosion of males were later than those of some females. In the case of two males (offspring in pupal and/or adult stages) in the same gallery system, most of the males coexisted in the condition of both different stages and different branch tunnels. These results imply that a mother beetle of X. pfeili determines the number of her eggs in response to the size of each branch tunnel (= amount of ambrosia fungus), and produces at least one male egg in the tunnel after laying some female eggs. [source] Effect of lindane on CYP-mediated steroid hormone metabolism in male mice following in utero exposureJOURNAL OF APPLIED TOXICOLOGY, Issue 8 2009Emma Di Consiglio Abstract A wide number of pesticides, including highly persistent organochlorinated compounds, such as lindane (LIN), may induce reproductive and developmental alterations by directly binding to the estrogen/androgen receptors or altering steroid hormone metabolism. In the present work, we have investigated whether LIN in utero exposure of CD1 mice affects the reproductive system in male offspring by causing an impairment of the CYP-dependent steroid hormone metabolism. Dam exposure to 25 mg kg,1 b.w. LIN occurred during critical developmental periods, from gestational days 9 to 16. Effects on hepatic CYP-mediated testosterone (TST) hydroxylase, aromatase activities and testicular parameters were tested at postnatal days (PND 50, 65,69, 100) that are critical for sexual maturation in CD1 mice. In the adult F1 mice significant changes of male reproductive endpoints (testis weight, spermatid number) as well as dramatic effects on CYP-mediated TST metabolism were observed on PND 65,69, in the absence of any of systemic toxicity. The levels of TST 6, - and 2, -hydroxylation and dehydrogenation showed the highest level of reduction, suggesting CYP 3A and 2C families as the major target of LIN induced effects. All changes were almost recovered on PND 100. No effects on aromatase activity were evidenced. Overall, these findings provide useful information for a better characterization of the LIN mode of action. They suggest that LIN-induced toxicity in males is linked to an impairment of steroid hormone homeostasis, due to CYP-mediated TST catabolism modulation and differs from LIN receptor-mediated mechanism previously reported in females. Copyright © 2009 John Wiley & Sons, Ltd. [source] Brood size and environmental conditions sex-specifically affect nestling immune response in the European starling Sturnus vulgarisJOURNAL OF AVIAN BIOLOGY, Issue 6 2005Eunice H. Chin In sexually size-dimorphic species, the larger sex can be more sensitive to stressful environmental conditions, often resulting in reduced growth and elevated mortality rates. Development of the immune system is regarded as highly resource dependent, and recent data suggest that nestling passerines experience a possible resource-based trade-off between growth and immunity. Given the hypothesized importance of maximizing growth for the larger sex, the corresponding immune system may also exhibit similar sensitivity to limited resources. To better understand how natural variation in brood size and resources might differentially affect growth and immune function in nestlings of a sexually size-dimorphic species, we examined the relationship between brood size and inter-sexual differences in cell-mediated immunity (CMI) and survival in European starling Sturnus vulgaris nestlings where males are larger in both mass and structural size. We hypothesized that male CMI response should be negatively impacted by increasing sibling competition (brood size), especially during periods of low resource availability. In a year of reduced parental provisioning rates and reduced chick growth rates, male offspring exhibited the predicted negative relationship, whereas female CMI response was unaffected. However, in a year of improved provisioning rates and chick growth, neither sex exhibited a negative relationship between immune response and brood size. Thus, natural variation in brood size can affect sex-specific immunity differently in offspring of a sexually size-dimorphic passerine. However, this relationship appears resource-dependent, suggesting that the hypothesized resource-based trade-off may be compensated for in years of adequate resource abundance. [source] Maternal and paternal condition effects on offspring phenotype in Telostylinus angusticollis (Diptera: Neriidae)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2007R. BONDURIANSKY Abstract It is widely recognized that maternal phenotype can have important effects on offspring, but paternal phenotype is generally assumed to have no influence in animals lacking paternal care. Nonetheless, selection may favour the transfer of environmentally acquired condition to offspring from both parents. Using a split-brood, cross-generational laboratory design, we manipulated a key environmental determinant of condition , larval diet quality , of parents and their offspring in the fly Telostylinus angusticollis, in which there is no evidence of paternal provisioning. Parental diet did not affect offspring survival, but high-condition mothers produced larger eggs, and their offspring developed more rapidly when on a poor larval diet. Maternal condition had no effect on adult body size of offspring. By contrast, large, high-condition fathers produced larger offspring, and follow-up assays showed that this paternal effect can be sufficient to increase mating success of male offspring and fecundity of female offspring. Our findings suggest that both mothers and fathers transfer their condition to offspring, but with effects on different offspring traits. Moreover, our results suggest that paternal effects can be important even in species lacking conventional forms of paternal care. In such species, the transfer of paternal condition to offspring could contribute to indirect selection on female mate preferences. [source] Can maternally transmitted endosymbionts facilitate the evolution of haplodiploidy?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2006J. ENGELSTÄDTER Abstract Whilst many invertebrate taxa are haplodiploid, the factors underlying the evolution of haplodiploidy remain unresolved. We investigate theoretically whether haplodiploidy might evolve as an outcome of the co-evolution between maternally inherited endosymbionts and their hosts. First, we substantially extend a recently developed model that involves maternally inherited endosymbionts that kill male offspring by eliminating the paternal genome. We also put forward a new hypothesis and develop a model that involves bacteria that induce cytoplasmic incompatibility (CI). Based on these models, we explore the co-evolutionary events that might occur between hosts and symbionts. We find that both with male-killers and CI-inducing endosymbionts, the hosts are likely to develop increased viability of haploid males, which can be considered a preadaptation to haplodiploidy. In addition, populations with haploidizing male-killers can in some cases evolve directly towards a genetic system of paternal genome elimination, a special form of haplodiploidy. These results are combined with consideration of mechanism and ecology to appraise the likelihood of male-killers and CI inducing bacteria being involved in the evolution of haplodiploidy. [source] Phenotypic and genetic variation in emergence and development time of a trimorphic damselflyJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2005J. ABBOTT Abstract Although colour polymorphisms in adult organisms of many taxa are often adaptive in the context of sexual selection or predation, genetic correlations between colour and other phenotypic traits expressed early in ontogeny could also play an important role in polymorphic systems. We studied phenotypic and genetic variation in development time among female colour morphs in the polymorphic damselfly Ischnura elegans in the field and by raising larvae in a common laboratory environment. In the field, the three different female morphs emerged at different times. Among laboratory-raised families, we found evidence of a significant correlation between maternal morph and larval development time in both sexes. This suggests that the phenotypic correlation between morph and emergence time in the field has a parallel in a genetic correlation between maternal colour and offspring development time. Maternal colour morph frequencies could thus potentially change as correlated responses to selection on larval emergence dates. The similar genetic correlation in male offspring suggests that sex-limitation in this system is incomplete, which may lead to an ontogenetic sexual conflict between selection for early male emergence (protandry) and emergence times associated with maternal morph. [source] Sexually antagonistic selection on primate sizeJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2002P. Lindenfors Abstract Male intrasexual selection in haplorhine primates has previously been shown to increase male size and to a lesser degree also female size. I address the following questions: (1) why does female size increase when the selection is on males, and (2) why does female size not increase to the same extent as that of males. The potential for correlational selection on females through increased resource competition was analysed with independent contrasts analyses. No such effect was found, nor did matched pairs comparisons reveal females to increase in size because of selection to bear larger male offspring. Instead further matched pairs analyses revealed higher female postpartum investment, as indicated by a longer lactation period, in more sexually selected species, also after correcting for body weight. Concerning the second question, independent contrast analyses showed that large size has had negative effects on female reproductive rate across the primate order. Matched-pairs analyses on haplorhines revealed that females of species in more polygynous clades have lower reproductive rates than females of species in less polygynous clades. This is also true after the effects of body weight are removed. These results, both when correcting for body weight and when not, suggest that sexual selection has shifted female size from one favouring female lifetime fecundity to one favouring male success in competition. This depicts antagonistic selection pressures on female size and a trade-off for females between the ecologically optimal size of their foremothers and the larger size that made their forefathers successful. [source] Absence of leukocyte microchimerism in oral lichen planus (OLP): an in situ hybridisation studyJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 7 2001T. Lombardi Abstract: Oral lichen planus (OLP) is a relatively common chronic inflammatory disease. The majority of patients are between 30 and 50 years of age with a higher incidence in females. The aetiology is unknown and various hypotheses on the pathogenic mechanisms, including autoimmunity, have been proposed over the years. In the present study, we investigated whether leukocyte microchimerism, a biological situation implicated in the aetiology of some autoimmune diseases, might play a role in the pathogenesis of OLP. We used in situ hybridisation to identify Y chromosome DNA in a series of formalin-fixed paraffin-embedded oral mucosa biopsies of women with established clinical and histological disease who had given birth to a male child. The positive control, two mucosal specimens from a man with OLP, showed over 90% of keratinocytes and cells within the inflammatory infiltrate, a positive nuclear signal. The negative control, biopsies from three women having carried only female foetuses and one nulliparous woman, all with OLP, did not show any nuclear signal. In the fifteen selected cases of OLP biopsies from women who had only male offspring, nucleated cells containing the Y chromosome were not detected within the chronic inflammatory infiltrate. These results suggest that unlike some other immunologically mediated diseases, leukocyte microchimerism does not seems to be involved in the pathogenesis of OLP. [source] Gender-Related Influences of Parental Alcoholism on the Prevalence of Psychiatric Illnesses: Analysis of the National Epidemiologic Survey on Alcohol and Related ConditionsALCOHOLISM, Issue 10 2010Peter T. Morgan Background:, Offspring of individuals with alcoholism are at increased risk for psychiatric illness, but the effects of gender on this risk are not well known. In this study, we tested the hypothesis that the gender of the parent with alcoholism and the gender of offspring affect the association between parental alcoholism and offspring psychiatric illness. Method:, We analyzed the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) data to examine the gender-specific prevalence of axis I and axis II disorders in 23,006 male and 17,368 female respondents with and without a history of paternal or maternal alcoholism. Adjusted odds ratios were calculated for the disorders based on gender and presence of maternal or paternal alcoholism. Results:, Maternal or paternal alcoholism was associated with a higher prevalence of every disorder examined, regardless of the gender of offspring. Gender-related differences in prevalences were present in nearly all examined disorders, and the association between parental alcoholism and offspring psychiatric disorders was significantly different in men and women. These differences included stronger associations in female offspring of men with alcoholism (alcohol abuse without dependence); in female offspring of women with alcoholism (mania, nicotine dependence, alcohol abuse, and schizoid personality disorder); in male offspring of men with alcoholism (mania); and in male offspring of women with alcoholism (panic disorder). Conclusions:, Interactions between gender and parental alcoholism were specific to certain disorders but varied in their effects, and in general female children of women with alcoholism appear at greatest risk for adult psychopathology. [source] Effects of a Novel Cognition-Enhancing Agent on Fetal Ethanol-Induced Learning DeficitsALCOHOLISM, Issue 10 2010Daniel D. Savage Background:, Drinking during pregnancy has been associated with learning disabilities in affected offspring. At present, there are no clinically effective pharmacotherapeutic interventions for these learning deficits. Here, we examined the effects of ABT-239, a histamine H3 receptor antagonist, on fetal ethanol-induced fear conditioning and spatial memory deficits. Methods and Results:, Long-Evans rat dams stably consumed a mean of 2.82 g ethanol/kg during a 4-hour period each day during pregnancy. This voluntary drinking pattern produced a mean peak serum ethanol level of 84 mg/dl. Maternal weight gain, litter size and birth weights were not different between the ethanol-consuming and control groups. Female adult offspring from the control and fetal alcohol-exposed (FAE) groups received saline or 1 mg ABT-239/kg 30 minutes prior to fear conditioning training. Three days later, freezing time to the context was significantly reduced in saline-treated FAE rats compared to control. Freezing time in ABT-239-treated FAE rats was not different than that in controls. In the spatial navigation study, adult male offspring received a single injection of saline or ABT-239 30 minutes prior to 12 training trials on a fixed platform version of the Morris Water Task. All rats reached the same performance asymptote on Trials 9 to 12 on Day 1. However, 4 days later, first-trial retention of platform location was significantly worse in the saline-treated FAE rats compared control offspring. Retention by ABT-239-treated FAE rats was similar to that by controls. ABT-239's effect on spatial memory retention in FAE rats was dose dependent. Conclusions:, These results suggest that ABT-239 administered prior to training can improve retention of acquired information by FAE offspring on more challenging versions of hippocampal-sensitive learning tasks. Further, the differential effects of ABT-239 in FAE offspring compared to controls raises questions about the impact of fetal ethanol exposure on histaminergic neurotransmission in affected offspring. [source] Priming Deficiency in Male Subjects at Risk for Alcoholism: The N4 During a Lexical Decision TaskALCOHOLISM, Issue 12 2009Bangalore N. Roopesh Background:, While there is extensive literature on the relationship between the P3 component of event-related potentials (ERPs) and risk for alcoholism, there are few published studies regarding other potentially important ERP components. One important candidate is the N4(00) component in the context of semantic processing, as abnormalities in this component have been reported for adult alcoholics. Method:, A semantic priming task was administered to nonalcohol dependent male offspring (18 to 25 years) of alcoholic fathers [high risk (HR) n = 23] and nonalcoholic fathers [low risk (LR) n = 28] to study whether the 2 groups differ in terms of the N4 component. Subjects were presented with 150 words and 150 nonwords. Among the words, 50 words (primed) were preceded by their antonyms (prime, n = 50), whereas the remaining 50 words were unprimed. For the analysis, N4 amplitude and latency as well as behavioral measures for the primed and unprimed words were considered. Results:, A significant interaction effect was observed between semantic condition and group, where HR subjects did not show N4 attenuation for primed stimuli. Conclusion:, The lack of N4 attenuation to primed stimuli and/or inability to differentiate between primed and unprimed stimuli, without latency and reaction time being affected, suggest deficits in semantic priming, especially in semantic expectancy and/or postlexical semantic processing in HR male offspring. Further, it indicates that it might be an electrophysiological endophenotype that reflects genetic vulnerability to develop alcoholism. [source] Protective Effect of Vitamin E Against Ethanol-Induced Hyperhomocysteinemia, DNA Damage, and Atrophy in the Developing Male Rat BrainALCOHOLISM, Issue 7 2009Alireza Shirpoor Background:, Chronic alcoholism leads to elevated plasma and brain homocysteine (Hcy) levels, as demonstrated by clinical investigations and animal experiments. It has been posited that elevated levels of Hcy mediate DNA damage, brain atrophy, and excitotoxicity. The current study sought to elucidate the effect of vitamin E on ethanol-induced hyperhomocysteinemia, DNA damage, and atrophy in the developing hippocampus and cerebellum of rats. Methods:, Pregnant Wistar rats received ethanol with or without vitamin E from gestation day 7 throughout lactation. Weight changes in the brain, hippocampus and cerebellum, DNA damage, and Hcy levels in the plasma, hippocampus, and cerebellum of male offspring were measured at the end of lactation. Results:, The results revealed that along with a significant decrease in brain, cerebellum, and hippocampus weights in animals that received alcohol, the levels of DNA damage and Hcy significantly increased. Significant amelioration of brain atrophy and DNA damage as well as restoration of the elevated level of Hcy to that of controls were found in vitamin E-treated rats. Conclusions:, These findings strongly support the idea that ethanol intake by dams during pregnancy and lactation induces Hcy-mediated oxidative stress in the developing hippocampus and cerebellum of offspring rats, and that these effects can be alleviated by vitamin E as an antioxidant. [source] Kinship and social structure of bobcats (Lynx rufus) inferred from microsatellite and radio-telemetry dataJOURNAL OF ZOOLOGY, Issue 4 2006J. E. Jane Abstract Kinship analysis using 12 microsatellites was compared with radio-telemetry data to examine the social structure of bobcats Lynx rufus in southern Texas. Genetically identified kinship relationships combined with capture data were used to reconstruct pedigrees. Three family groups were constructed from parent/offspring pairs identified from shared alleles. All parents identified by genetic analysis had established home ranges. Individuals with no distinct home ranges were not genetically observed to have offspring among the bobcats sampled. This suggests that establishing a home range is necessary for bobcats to breed. Of three identified male offspring and three identified female offspring, two female offspring were philopatric. These females became a part of the breeding population in their natal area. Among sibling pairs that included nine female and four male individuals, four females and one male were residents suggesting male-biased dispersal. [source] Mix and match , hybridization reveals hidden complexity in seal breeding behaviourMOLECULAR ECOLOGY, Issue 15 2007WILLIAM AMOS Not so long ago, mammalian breeding systems were seen as dominated by males fighting each other for the right to mate with passive females. Genetic parentage analysis has been instrumental in changing this view and exposing the key role of female choice. Some of the most interesting discoveries have emerged from work on seals, where extreme polygyny is common but females often seem to have a bigger say than was previously thought. A remarkable case in question involves Macquarie Island, where three species of fur seal recently formed a mixed breeding colony (Goldsworthy et al. 1999). Here, the true colours of both sexes lie unusually exposed, because classical models predict that males of the biggest species will dominate the beach and force females of smaller species to conceive mainly hybrid pups. In a fascinating paper in this issue of Molecular Ecology, Lancaster and colleagues (Lancaster et al. 2007) show that females are not this naïve. Although happy to gain protection for most of the season by sitting in the territory of one of the largest males, regardless of whether he is the same species, females almost always conceive to one of their own kind. The females do this, not because any hybrid male offspring they conceive will be sickly and fail to hold good territories, but because females who pup in their hybrid son's territories will be disproportionately likely to mate elsewhere. Hybrid males seem physically fit but sexually unattractive! [source] A dose-response relationship between maternal smoking during late pregnancy and adult intelligence in male offspringPAEDIATRIC & PERINATAL EPIDEMIOLOGY, Issue 1 2005Erik Lykke Mortensen Summary An association between maternal smoking during pregnancy and cognitive and behavioural development has been observed in several studies, but potential effects of maternal smoking on offspring adult intelligence have not been investigated. The objective of the present study was to investigate a potential association between maternal smoking during pregnancy and offspring intelligence in young adulthood. Adult intelligence was assessed at the mean age of 18.7 years by a military draft board intelligence test (Børge Priens Prøve) for 3044 singleton males from the Copenhagen Perinatal Cohort with information regarding maternal smoking during the third trimester coded into five categories (about 50% of the mothers were smokers). The following potential confounders were included as covariates in multivariable analyses: parental social status and education, single mother status, mother's height and age, number of pregnancies, and gestational age. In separate analyses, birthweight and length were also included as covariates. Maternal cigarette smoking during the third trimester, adjusted for the seven covariates, showed a negative association with offspring adult intelligence (P = 0.0001). The mean difference between the no-smoking and the heaviest smoking category amounted to 0.41 standard deviation, corresponding to an IQ difference of 6.2 points [95% confidence interval 0.14, 0.68]. The association remained significant when further adjusted for birthweight and length (P = 0.007). Both unadjusted and adjusted means suggested a dose-response relationship between maternal smoking during pregnancy and offspring adult intelligence. When subjects with missing data were excluded, essentially the same results were obtained in the reduced sample (n = 1829). These results suggest that smoking during pregnancy may have long-term negative consequences on offspring adult intelligence. [source] | |||||||||||||||||||||||||||||||