BREAKDOWN OF ISOLATION MECHANISMS IN TWO SPECIES OF CAPTIVE JUNGLEFOWL (<i>GALLUS GALLUS</i>AND<i>GALLUS SONNERATII</i>)

Morejohn, G. Victor

doi:10.1111/j.1558-5646.1968.tb03993.x

Cited by 16 publications

(11 citation statements)

References 15 publications

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“…We cannot exclude the possibility that yellow skin was introgressed to the red junglefowl by hybridization with grey junglefowl prior to domestication, but it is much more plausible that introgression was facilitated by human activities. The red and grey junglefowls are full species as demonstrated by the fact that hybridization does not occur in the wild [17] and when attempted in captivity, only a cross between grey cocks and red hens produced mostly sterile offspring [19]. Hybridization between grey junglefowl and domesticated fowl, however, have been reported in the vicinity of villages within the area of contact between the two wild species [17], suggesting that the introgression of yellow skin into domestic birds took place after chickens were initially domesticated.…”

Section: Discussionmentioning

confidence: 99%

Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken

et al. 2008

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Yellow skin is an abundant phenotype among domestic chickens and is caused by a recessive allele (W*Y) that allows deposition of yellow carotenoids in the skin. Here we show that yellow skin is caused by one or more cis-acting and tissue-specific regulatory mutation(s) that inhibit expression of BCDO2 (beta-carotene dioxygenase 2) in skin. Our data imply that carotenoids are taken up from the circulation in both genotypes but are degraded by BCDO2 in skin from animals carrying the white skin allele (W*W). Surprisingly, our results demonstrate that yellow skin does not originate from the red junglefowl (Gallus gallus), the presumed sole wild ancestor of the domestic chicken, but most likely from the closely related grey junglefowl (Gallus sonneratii). This is the first conclusive evidence for a hybrid origin of the domestic chicken, and it has important implications for our views of the domestication process.

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Section: Discussionmentioning

confidence: 99%

Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken

et al. 2008

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“…We collected information from the literature on experimentally controlled crosses that were performed in captivity among different galliform species (Haig Thomas & Huxley, 1927;Shaklee & Knox, 1954;Lorenz, Asmundson & Wilson, 1956;Asmundson & Lorenz, 1957;Sandnes, 1957;Olsen, 1960;Wilcox & Clark, 1961;Lepori, 1964;Taibel, 1964Taibel, , 1974Maru & Ishijima, 1968;Morejohn, 1968;Higuchi, 1971;Johnsgard, 1973;Cink, 1975;Skjervold & Mjelstad, 1992;Deregnaucourt, Guyomarc'h & Aebischer, 2002;Khosravinia, Narasimha Murthy & Kumar, 2005). These records include the number of laid eggs, fertilized eggs and hatched eggs in interspecific crosses, in crosses between first-generation (F 1) hybrids (which generate a second hybrid generation or F2) and in backcrosses between hybrids and their parental species.…”

Section: Reproductive Isolation Indicesmentioning

confidence: 99%

Evolution of postzygotic reproductive isolation in galliform birds: analysis of first and second hybrid generations and backcrosses

Arrieta

Lijtmaer

Tubaro

2013

Biol J Linn Soc Lond

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The process of speciation is a crucial aspect of evolutionary biology. In this study, we analysed the patterns of evolution of postzygotic reproductive isolation in Galliformes using information on hybridization and genetic distance among species. Four main patterns arose: (1) hybrid inviability and sterility in F1 hybrids increase as species diverge; (2) the presence of geographical overlap does not affect the evolution of postzygotic isolation; (3) the galliforms follow Haldane's rule; (4) hybrid inviability is higher in F2 than in F1 hybrids, but does not appear to be increased in the backcrosses. This study contributes to the growing evidence suggesting that the patterns of evolution of postzygotic isolation and the process of speciation are shared among avian groups (and animals in general). In particular, our results support the notion of F2 hybrid inviability as being key for the maintenance of species genetic integrity when prezygotic isolation barriers are overcome in closely related species, in which postzygotic isolation in the F1 hybrid might still not be fully developed. To the contrary, hybrids from backcrosses did not show serious inviability problems (at least not more than F1 hybrids), demonstrating that they could generate gene flow among bird species.

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“…These two species do not hybridize in the wild (Johnsgard ), and a cross in captivity between grey junglefowl cocks and red junglefowl hens produced mostly sterile progeny (Morejohn ). However, hybridization between grey junglefowl and domestic chickens has been reported (Johnsgard ), suggesting that introgression of the yellow skin region occurred after domestication.…”

Section: Examples Of Adaptive Introgressionmentioning

confidence: 99%

Adaptive introgression in animals: examples and comparison to new mutation and standing variation as sources of adaptive variation

2013

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Adaptive genetic variation has been thought to originate primarily from either new mutation or standing variation. Another potential source of adaptive variation is adaptive variants from other (donor) species that are introgressed into the (recipient) species, termed adaptive introgression. Here, the various attributes of these three potential sources of adaptive variation are compared. For example, the rate of adaptive change is generally thought to be faster from standing variation, slower from mutation and potentially intermediate from adaptive introgression. Additionally, the higher initial frequency of adaptive variation from standing variation and lower initial frequency from mutation might result in a higher probability of fixation of the adaptive variants for standing variation. Adaptive variation from introgression might have higher initial frequency than new adaptive mutations but lower than that from standing variation, again making the impact of adaptive introgression variation potentially intermediate. Adaptive introgressive variants might have multiple changes within a gene and affect multiple loci, an advantage also potentially found for adaptive standing variation but not for new adaptive mutants. The processes that might produce a common variant in two taxa, convergence, trans-species polymorphism from incomplete lineage sorting or from balancing selection and adaptive introgression, are also compared. Finally, potential examples of adaptive introgression in animals, including balancing selection for multiple alleles for major histocompatibility complex (MHC), S and csd genes, pesticide resistance in mice, black colour in wolves and white colour in coyotes, Neanderthal or Denisovan ancestry in humans, mimicry genes in Heliconius butterflies, beak traits in Darwin's finches, yellow skin in chickens and non-native ancestry in an endangered native salamander, are examined.

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BREAKDOWN OF ISOLATION MECHANISMS IN TWO SPECIES OF CAPTIVE JUNGLEFOWL (GALLUS GALLUSANDGALLUS SONNERATII)

Cited by 16 publications

References 15 publications

Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken

Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken

Evolution of postzygotic reproductive isolation in galliform birds: analysis of first and second hybrid generations and backcrosses

Adaptive introgression in animals: examples and comparison to new mutation and standing variation as sources of adaptive variation

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