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Hybrid Males (hybrid + male)

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Life Sciences100%

Terms modified by Hybrid Males

  • hybrid male sterility
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    Selected Abstracts

    Mix and match , hybridization reveals hidden complexity in seal breeding behaviour

    MOLECULAR ECOLOGY, Issue 15 2007
    WILLIAM 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]

    Mating Call Discrimination in Female European (Coturnix c. coturnix) and Japanese Quail (Coturnix c. japonica)

    ETHOLOGY, Issue 2 2003
    Sébastien Derégnaucourt
    Each year, thousands of domestic Japanese and hybrid quails are released within the breeding range of the European quail. We showed recently that no post-zygotic isolating mechanisms have yet been established between these subspecies. The aim of this study was to investigate whether pre-zygotic mechanisms are strong enough to prevent hybridization. We tested the level of subspecies selectivity in females of European and Japanese quail respectively using playbacks of European, hybrid and Japanese male mating calls. European quail females emitted the greatest number of rally calls in response to mating calls by conspecific males. Their responses were the weakest to mating calls produced by males of the other subspecies and intermediate to mating calls by hybrid males. In contrast, Japanese quails produced similar responses to all types of mating calls. These results suggest that mixed pairs could form in the wild. The European quail could thus become one of the most endangered galliforms of the Western Palearctic. [source]

    Hybrid incompatibility is consistent with a hybrid origin of Heliconius heurippa Hewitson from its close relatives, Heliconius cydno Doubleday and Heliconius melpomene Linnaeus

    JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2005
    C. A. Salazar
    Abstract Shared ancestral variation and introgression complicates the reconstruction of phylogenetic relationships among closely related taxa. Here we use overall genomic compatibility as an alternative estimate of species relationships in a group where divergence is rapid and genetic exchange is common. Heliconius heurippa, a butterfly species endemic to Colombia, has a colour pattern genetically intermediate between H. cydno and H. melpomene: its hindwing is nearly indistinguishable from that of H. melpomene and its forewing band is an intermediate phenotype between both species. This observation has lead to the suggestion that the pattern of H. heurippa arose through hybridization. We present a genetic analysis of hybrid compatibility in crosses between the three taxa. Heliconius heurippa × H. cydno and female H. melpomene × male H. heurippa yield fertile and viable F1 hybrids, but male H. melpomene × female H. heurippa crosses yield sterile F1 females. In contrast, Haldane's rule has previously been detected between H. melpomene and H cydno in both directions. Therefore, H. heurippa is most closely related to H. cydno, with some evidence for introgression of genes from H. melpomene. The results are compatible with the hypothesis of a hybrid origin for H. heurippa. In addition, backcrosses using F1 hybrid males provide evidence for a large Z(X)-chromosome effect on sterility and for recessive autosomal sterility factors as predicted by Dominance Theory. [source]

    Lower reproductive success in hybrid fur seal males indicates fitness costs to hybridization

    MOLECULAR ECOLOGY, Issue 15 2007
    MELANIE L. LANCASTER
    Abstract Hybridization among organisms can potentially contribute to the processes of evolution, but this depends on the fitness of hybrids relative to parental species. A small, recently formed population of fur seals on subantarctic Macquarie Island contains a high proportion of hybrids (17,30%) derived from combinations of three parental species: Antarctic, subantarctic and New Zealand fur seals. Mitochondrial control-region data (restriction fragment length polymorphisms) and nine microsatellites were used to determine the species composition of breeding adults, and hybrid male fitness was measured by comparing reproductive success (number of genetically inferred paternities) of hybrid and pure-species territory males over 6 years. No correlations were found between male reproductive success and three genetic measures of outbreeding, but this may be due to a relatively small number of dominant males analysed. Territory males fathered 63% of pups, but hybrid males had lower reproductive success than pure-species males despite having the same ability to hold territories. A greater proportion of females in hybrid male territories conceived extra-territorially than those in territories of pure-species males, and most (70 of 82) mated with conspecifics. This suggests the presence of reproductive isolating mechanisms that promote positive assortative mating and reduce the production of hybrid offspring. Although we found no evidence for male sterility in the population, mechanisms that reduce lifetime reproductive success may act to decrease the frequency of hybrids. Our study has identified a disadvantage of hybridization , reduced reproductive success of hybrid sons , that may be contributing to the persistence of pure lineages at Macquarie Island and the temporal decline in hybridization observed there. [source]