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Author Moritz, Gillian L. ♦ Lim, rman T. L. ♦ Neitz, Maureen ♦ Peichl, Leo ♦ Dominy, Nathaniel J.
Source SpringerLink
Content type Text
Publisher Springer US
File Format PDF
Copyright Year ©2013
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Life sciences; biology
Subject Keyword Retina ♦ Visual pigment ♦ Dermoptera ♦ Scandentia ♦ Primates ♦ Evolutionary Biology ♦ Ecology ♦ Developmental Biology ♦ Human Genetics ♦ Animal Genetics and Genomics
Abstract A nocturnal activity pattern is central to almost all hypotheses on the adaptive origins of primates. This enduring view has been challenged in recent years on the basis of variation in the opsin genes of nocturnal primates. A correspondence between the opsin genes and activity patterns of species in Euarchonta—the superordinal group that includes the orders Primates, Dermoptera (colugos), and Scandentia (treeshrews)—could prove instructive, yet the basic biology of the dermopteran visual system is practically unknown. Here we show that the eye of the Sunda colugo (Galeopterus variegatus) lacks a tapetum lucidum and has an avascular retina, and we report on the expression and spectral sensitivity of cone photopigments. We found that Sunda colugos have intact short wavelength sensitive (S-) and long wavelength sensitive (L-) opsin genes, and that both opsins are expressed in cone photoreceptors of the retina. The inferred peak spectral sensitivities are 451 and 562 nm, respectively. In line with adaptation to nocturnal vision, cone densities are low. Surprisingly, a majority of S-cones coexpress some L-opsin. We also show that the ratio of rates of nonsynonymous to synonymous substitutions of exon 1 of the S-opsin gene is indicative of purifying selection. Taken together, our results suggest that natural selection has favored a functional S-opsin in a nocturnal lineage for at least 45 million years. Accordingly, a nocturnal activity pattern remains the most likely ancestral character state of euprimates.
ISSN 00713260
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2013-04-17
Publisher Place Boston
e-ISSN 19342845
Journal Evolutionary Biology
Volume Number 40
Issue Number 4
Page Count 12
Starting Page 542
Ending Page 553

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Source: SpringerLink