Sequence divergence of the red and green visual pigments in great apes and humans.
AUTOR(ES)
Deeb, S S
RESUMO
We have determined the coding sequences of red and green visual pigment genes of the chimpanzee, gorilla, and orangutan. The deduced amino acid sequences of these pigments are highly homologous to the equivalent human pigments. None of the amino acid differences occurred at sites that were previously shown to influence pigment absorption characteristics. Therefore, we predict the spectra of red and green pigments of the apes to have wavelengths of maximum absorption that differ by < 2 nm from the equivalent human pigments and that color vision in these nonhuman primates will be very similar, if not identical, to that in humans. A total of 14 within-species polymorphisms (6 involving silent substitutions) were observed in the coding sequences of the red and green pigment genes of the great apes. Remarkably, the polymorphisms at 6 of these sites had been observed in human populations, suggesting that they predated the evolution of higher primates. Alleles at polymorphic sites were often shared between the red and green pigment genes. The average synonymous rate of divergence of red from green sequences was approximately 1/10th that estimated for other proteins of higher primates, indicating the involvement of gene conversion in generating these polymorphisms. The high degree of homology and juxtaposition of these two genes on the X chromosome has promoted unequal recombination and/or gene conversion that led to sequence homogenization. However, natural selection operated to maintain the degree of separation in peak absorbance between the red and green pigments that resulted in optimal chromatic discrimination. This represents a unique case of molecular coevolution between two homologous genes that functionally interact at the behavioral level.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=44379Documentos Relacionados
- Recombination Has Little Effect on the Rate of Sequence Divergence in Pseudoautosomal Boundary 1 Among Humans and Great Apes
- A neuronal morphologic type unique to humans and great apes
- Lineage-Specific Expansions of Retroviral Insertions within the Genomes of African Great Apes but Not Humans and Orangutans
- Fluorescence in situ hybridization analysis of keratinocyte growth factor gene amplification and dispersion in evolution of great apes and humans
- Proprioceptive, visual and vestibular thresholds for the perception of sway during standing in humans.