| 1. |
- Haas, Fredrik, et al.
(author)
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An analysis of population genetic differentiation and genotype-phenotype association across the hybrid zone of carrion and hooded crows using microsatellites and MC1R.
- 2009
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In: Molecular Ecology. - 0962-1083. ; 18:2, s. 294-305
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Journal article (peer-reviewed)abstract
- Abstract The all black carrion crow (Corvus corone corone) and the grey and black hooded crow (Corvus corone cornix) meet in a narrow hybrid zone across Europe. To evaluate the degree of genetic differentiation over the hybrid zone, we genotyped crows from the centre and edges of the zone, and from allopatric populations in northern (Scotland-Denmark-Sweden) and southern Europe (western-central northern Italy), at 18 microsatellites and at a plumage candidate gene, the MC1R gene. Allopatric and edge populations were significantly differentiated on microsatellites, and populations were isolated by distance over the hybrid zone in Italy. Single-locus analyses showed that one locus, CmeH9, differentiated populations on different sides of the zone at the same time as showing only weak separation of populations on the same side of the zone. Within the hybrid zone there was no differentiation of phenotypes at CmeH9 or at the set of microsatellites, no excess of heterozygotes among hybrids and low levels of linkage disequilibrium between markers. We did not detect any association between phenotypes and nucleotide variation at MC1R, and the two most common haplotypes occurred in very similar frequencies in carrion and hooded crows. That we found a similar degree of genetic differentiation between allopatric and edge populations irrespectively of their location in relation to the hybrid zone, no differentiation between phenotypes within the hybrid zone, and neither heterozygote excess nor consistent linkage disequilibrium in the hybrid zone, is striking considering that carrion and hooded crows are phenotypically distinct and sometimes recognised as separate species.
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| 2. |
- Haitina, Tatjana, et al.
(author)
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High diversity in functional properties of melanocortin 1 receptor (MC1R) in divergent primate species is more strongly associated with phylogeny than coat color
- 2007
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In: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 24:9, s. 2001-2008
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Journal article (peer-reviewed)abstract
- We have characterized the biochemical function of the melanocortin1 receptor (MC1R), a critical regulator of melanin synthesis,from 9 phylogenetically diverse primate species with varyingcoat colors. There is substantial diversity in melanocyte-stimulatinghormone (MSH) binding affinity and basal levels of activityin the cloned MC1Rs. MSH binding was lost independently in lemurand New World monkey lineages, whereas high basal levels ofMC1R activity occur in lemurs and some New World monkeys andOld World monkeys. Highest levels of basal activity were foundin the MC1R of ruffed lemurs, which have the E94K mutation thatleads to constitutive activation in other species. In 3 species(2 lemurs and the howler monkey), we report the novel findingthat binding and inhibition of MC1R by agouti signaling protein(ASIP) can occur when MSH binding has been lost, thus enablingcontinuing regulation of the melanin type via ASIP expression.Together, these findings can explain the previous paradox ofa predominantly pheomelanic coat in the red ruffed lemur (Vareciarubra). The presence of a functional, MSH-responsive MC1R inorangutan demonstrates that the mechanism of red hair generationin this ape is different from the prevalent mechanism in Europeanhuman populations. Overall, we have found unexpected diversityin MC1R function among primates and show that the evolutionof the regulatory control of MC1R activity occurs by independentvariation of 3 distinct mechanisms: basal MC1R activity, MSHbinding and activation, and ASIP binding and inhibition. Thisdiversity of function is broadly associated with primate phylogenyand does not have a simple relation to coat color phenotypewithin primate clades.
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