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Maternal Inheritance (maternal + inheritance)
Selected AbstractsPostnatal changes in the expression of genes located in the callipyge region in sheep skeletal muscleANIMAL GENETICS, Issue 6 2006A. C. Perkins Summary The expression of five genes surrounding the callipyge (CLPG) mutation was analysed in skeletal muscles from lambs at one prenatal and two postnatal ages that coincide with the onset and establishment of muscle hypertrophy. Genotype-specific changes in transcript abundance were detected for paternal allele-specific DLK1 and PEG11 (the official symbol of the latter is RTL1) and the maternal allele-specific MEG3, PEG11AS and MEG8 when the mutation was inherited in cis. There were differences in the temporal and muscle-specific effects on expression between the maternal allele-specific genes and paternal allele-specific genes. Maternal inheritance of the CLPG allele had a significant effect on the expression of MEG3 and MEG8 at prenatal and postnatal ages, whereas paternal inheritance of DLK1 and PEG11 only affected postnatal expression. Genotype-specific changes in PEG11AS expression were detected only in prenatal muscle. Maternal inheritance of the mutation caused similar changes in MEG3 and MEG8 expression in the semimembranosus, which undergoes hypertrophy, and the supraspinatus, which does not hypertrophy. Paternal inheritance of the mutation caused changes in PEG11 expression in both muscles, although the magnitude of expression in semimembranosus was more than 100-fold greater than in supraspinatus. DLK1 expression was upregulated in callipyge animals at both postnatal ages in the semimembranosus, but there was no effect of genotype on DLK1 expression in the supraspinatus at any age. Increased DLK1 expression was likely the primary cause of muscle hypertrophy, but a contribution of PEG11 to the phenotype cannot be ruled out based on gene expression. [source] DO RECENT FINDINGS IN PLANT MITOCHONDRIAL MOLECULAR AND POPULATION GENETICS HAVE IMPLICATIONS FOR THE STUDY OF GYNODIOECY AND CYTONUCLEAR CONFLICT?EVOLUTION, Issue 5 2008David E. McCauley The coexistence of females and hermaphrodites in plant populations, or gynodioecy, is a puzzle recognized by Darwin. Correns identified cytoplasmic inheritance of one component of sex expression, now known as cytoplasmic male sterility (CMS). Lewis established cytonuclear inheritance of gynodioecy as an example of genetic conflict. Although biologists have since developed an understanding of the mechanisms allowing the joint maintenance of CMS and nuclear male fertility restorer genes, puzzles remain concerning the inheritance of sex expression and mechanisms governing the origination of CMS. Much of the theory of gynodioecy rests on the assumption of maternal inheritance of the mitochondrial genome. Here we review recent studies of the genetics of plant mitochondria, and their implications for the evolution and transmission of CMS. New studies of intragenomic recombination provide a plausible origin for the chimeric ORFs that characterize CMS. Moreover, evidence suggests that nonmaternal inheritance of mitochondria may be more common than once believed. These findings may have consequences for the maintenance of cytonuclear polymorphism, mitochondrial recombination, generation of gynomonoecious phenotypes, and interpretation of experimental crosses. Finally we point out that CMS can alter the nature of the cytonuclear conflict that may have originally selected for uniparental inheritance. [source] Fish mitochondrial genomics: sequence, inheritance and functional variationJOURNAL OF FISH BIOLOGY, Issue 2 2008K. H. Brown Mitochondrial genomic research currently primarily focuses on the analysis and understanding of how mitochondrial mutations produce detrimental phenotypes in humans. Reasons for this focus on negative impacts include the large number of human diseases that are known to result from specific mitochondrial genomes, and the long held belief that mitochondria change only through the accumulation of mutations due to its clonal, maternal inheritance. Recent studies are beginning to challenge these preconceptions and have shown that mitochondrial genomes can have significant positive impacts. Although the number of studies using fishes as models in mitochondrial research is limited, many fish model species provide excellent opportunity for furthering the understanding of mitochondrial genomes, their interactions with the nuclear genome, the potential for understanding the mechanisms of how functional variation effects organisms and how selection for positive functional variation effects population variation. [source] DISAPPEARANCE OF MALE MITOCHONDRIAL DNA AFTER THE FOUR-CELL STAGE IN SPOROPHYTES OF THE ISOGAMOUS BROWN ALGA SCYTOSIPHON LOMENTARIA (SCYTOSIPHONACEAE, PHAEOPHYCEAE),JOURNAL OF PHYCOLOGY, Issue 1 2010Kei Kimura Mitochondrial DNA (mtDNA) of the isogamous brown alga Scytosiphon lomentaria (Lyngb.) Link is inherited maternally. We used molecular biological and morphological analyses to investigate the fate of male mitochondria. Ultrastructural observations showed that the number of 25 mitochondria in a zygote coincided with the number of mitochondria derived from male and female gametes. This number remained almost constant during the first cell division. Strain-specific PCR in single germlings suggested that mtDNA derived from the female gamete remained in the germling during development, while the male mtDNA gradually and selectively disappeared after the four-cell stage. One week after fertilization, male mtDNA had disappeared in sporophytic cells. Using bisulfite DNA modification and methylation mapping assays, we found that the degree of methylation on three analyzed sites of mtDNA was not different between male and female gametes, suggesting that maternal inheritance of mtDNA is not defined by its methylation. This study indicates that the mechanism of selective elimination of male mtDNA is present in each cell of a four-celled sporophyte and that it does not depend on different degrees of DNA methylation between male and female mtDNA. [source] Chloroplast diversity in Vouacapoua americana (Caesalpiniaceae), a neotropical forest treeMOLECULAR ECOLOGY, Issue 9 2000C. Dutech Abstract The chloroplast genome has been widely used to describe genetic diversity in plant species. Its maternal inheritance in numerous angiosperm species and low mutation rate are suitable characters when inferring historical events such as possible recolonization routes. Here we have studied chloroplast DNA variation using PCR,RFLP (polymerase chain reaction,restriction fragment length polymorphism) with seven pairs of primers and four restriction enzymes in 14 populations of Vouacapoua americana (Caesalpiniaceae) a neotropical tree sampled throughout French Guiana. Population diversity (Hs), total gene diversity (Ht) and differentiation among populations (GST) were estimated using Nei's method as 0.09, 0.87 and 0.89, respectively. This is consistent with the limited gene flow associated with synzoochory in this species. The genetic structure observed in the north of French Guiana suggests that historical events such as contractions and recent recolonizations have had a large impact on the distribution of genetic diversity in this species. [source] Reciprocal hybrid formation of Spartina in San Francisco BayMOLECULAR ECOLOGY, Issue 6 2000C. K. Anttila Abstract Diversity in the tRNALEU1 intron of the chloroplast genome of Spartina was used to study hybridization of native California cordgrass, Spartina foliosa, with S. alterniflora, introduced to San Francisco Bay , 25 years ago. We sequenced 544 bases of the tRNALEU1 intron and found three polymorphic sites, a pyrimidine transition at site 126 and transversions at sites 382 and 430. Spartina from outside of San Francisco Bay, where hybridization between these species is impossible, gave cpDNA genotypes of the parental species. S. foliosa had a single chloroplast haplotype, CCT, and this was unique to California cordgrass. S. alterniflora from the native range along the Atlantic coast of North America had three chloroplast haplotypes, CAT, TAA, and TAT. Hybrids were discriminated by random amplified polymorphic DNA (RAPD) phenotypes developed in a previous study. We found one hybrid that contained a cpDNA haplotype unknown in either parental species (TCT). The most significant finding was that hybridization proceeds in both directions, assuming maternal inheritance of cpDNA; 26 of the 36 hybrid Spartina plants from San Francisco Bay contained the S. foliosa haplotype, nine contained haplotypes of the invading S. alterniflora, and one had the cpDNA of unknown origin. Furthermore, cpDNA of both parental species was distributed throughout the broad range of RAPD phenotypes, suggesting ongoing contributions to the hybrid swarm from both. The preponderance of S. foliosa cpDNA has entered the hybrid swarm indirectly, we propose, from F1s that backcross to S. foliosa. Flowering of the native precedes by several weeks that of the invading species, with little overlap between the two. Thus, F1 hybrids would be rare and sired by the last S. foliosa pollen upon the first S. alterniflora stigmas. The native species produces little pollen and this has low viability. An intermediate flowering time of hybrids as well as pollen that is more vigourous and abundant than that of the native species would predispose F1s to high fitness in a vast sea of native ovules. Thus, spread of hybrids to other S. foliosa marshes could be an even greater threat to the native species than introductions of alien S. alterniflora. [source] Differential expression of the GTL2 gene within the callipyge region of ovine chromosome 18ANIMAL GENETICS, Issue 5 2001C. A. Bidwell The inheritance pattern of the skeletal muscle hypertrophy phenotype caused by the callipyge gene has been characterized as polar overdominance. We hypothesized that this trait may be caused by a gain or loss of gene expression because of the reversible nature of the phenotype in paternal vs. maternal inheritance. Suppression subtraction cDNA probes were made from skeletal muscle mRNA of normal (NN) and callipyge (CPatNMat) animals and hybridized to Southern blots containing bacterial artificial chromosomes (BACs) that comprise a physical contig of the callipyge region. The CN,NN probes hybridized to two ovine and seven bovine BACs. Sequence analysis of fragments within those BACs indicated short regions of similarity to mouse gene trap locus (gtl2). Northern blots analysis of RNA from hypertrophy-responsive muscles show a population of GTL2 mRNA centred around 2.4 kb that were abundantly expressed in 14-day prenatal NN and CPatNMat lambs but were down-regulated in day 14 and day 56 postnatal NN lambs. The expression of GTL2 remained elevated in 14- and 56-day-old CPatNMat lambs as well as in 56-day-old NPatCMat and CC lambs. Expression of GTL2 in the supraspinatus, which does not undergo hypertrophy, was very low for all genotypes and ages. Isolation of cDNA sequences show extensive alternative splicing and a lack of codon bias suggesting that GTL2 does not encode a protein. The mutation of the callipyge allele has altered postnatal expression of GTL2 in muscles that undergo hypertrophy and will help identify mechanisms involved in growth, genomic imprinting and polar overdominance. [source] Production of biopharmaceuticals and vaccines in plants via the chloroplast genomeBIOTECHNOLOGY JOURNAL, Issue 10 2006Henry Daniell Dr.Article first published online: 27 SEP 200 Abstract Transgenic plants offer many advantages, including low cost of production (by elimination of fermenters), storage and transportation; heat stability; and absence of human pathogens. When therapeutic proteins are orally delivered, plant cells protect antigens in the stomach through bioencapsulation and eliminate the need for expensive purification and sterile injections, in addition to development of both systemic and mucosal immunity. Chloroplast genetic engineering offers several advantages, including high levels of transgene expression, transgene containment via maternal inheritance and multi-gene expression in a single transformation event. Hyper-expression of vaccine antigens against cholera, tetanus, anthrax, plague or canine parvovirus (4,31% of total soluble protein, tsp) in transgenic chloroplasts (leaves) or non-green plastids (carrots, tomato), as well as the availability of antibiotic-free selectable markers or the ability to excise selectable marker genes, facilitate oral delivery. Hyper-expression of several therapeutic proteins, including human serum albumin (11.1% tsp), somatotropin (7% tsp), interferon-gamma (6% tsp), anti-microbial peptide (21.5% tsp), facilitates efficient and economic purification. Also, the presence of chaperones and enzymes in chloroplasts facilitate assembly of complex multi-subunit proteins and correct folding of human blood proteins with proper disulfide bonds. Functionality of chloroplast-derived vaccine antigens and therapeutic proteins has been demonstrated by several assays, including the macrophage lysis assay, GM1-ganglioside binding assay, protection of HeLa cells or human lung carcinoma cells against encephalomyocarditis virus, systemic immune response, protection against pathogen challenge, and growth or inhibition of cell cultures. Thus, transgenic chloroplasts are ideal bioreactors for production of functional human and animal therapeutic proteins in an environmentally friendly manner. [source] | ||||||||||