Molecular evolution of cytochrome \u3ci\u3eb\u3c/i\u3e in high- and low-altitude deer mice (genus \u3ci\u3ePeromyscus\u3c/i\u3e)

Patterns of amino-acid polymorphism in human mitochondrial genes have been interpreted as evidence for divergent selection among populations that inhabit climatically distinct environments. If similar patterns are mirrored in other broadly distributed mammalian species, then adaptive modifications of mitochondrial protein function may be detected in comparisons among locally adapted populations of a single wide-ranging species, or among closely related species that have adapted to different environments. Here, we test for evidence of positive selection on cytochrome b variation within and among species of the ecologically diverse rodent genus Peromyscus. We used likelihood-based comparisons of synonymous and nonsynonymous substitution rates to test for evidence of divergent selection between high- and low-altitude haplogroups of the deer mouse, Peromyscus maniculatus. We also tested for evidence of divergent selection among different species of Peromyscus that inhabit different thermal environments. In contrast to the purported evidence for positive selection on mitochondrial proteins in humans and other nonhuman mammals, results of our tests suggest that the evolution of cytochrome b in Peromyscus is chiefly governed by purifying selection

Molecular evolution of cytochrome \u3ci\u3eb\u3c/i\u3e in high- and low-altitude deer mice (genus \u3ci\u3ePeromyscus\u3c/i\u3e)

Patterns of amino-acid polymorphism in human mitochondrial genes have been interpreted as evidence for divergent selection among populations that inhabit climatically distinct environments. If similar patterns are mirrored in other broadly distributed mammalian species, then adaptive modifications of mitochondrial protein function may be detected in comparisons among locally adapted populations of a single wide-ranging species, or among closely related species that have adapted to different environments. Here, we test for evidence of positive selection on cytochrome b variation within and among species of the ecologically diverse rodent genus Peromyscus. We used likelihood-based comparisons of synonymous and nonsynonymous substitution rates to test for evidence of divergent selection between high- and low-altitude haplogroups of the deer mouse, Peromyscus maniculatus. We also tested for evidence of divergent selection among different species of Peromyscus that inhabit different thermal environments. In contrast to the purported evidence for positive selection on mitochondrial proteins in humans and other nonhuman mammals, results of our tests suggest that the evolution of cytochrome b in Peromyscus is chiefly governed by purifying selection

Polarization Transfer in Inelastic Proton Scattering from 12-C and 16-O

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

A Test of the Coplanar and Far-side Features of Intermediate Energy (d,p) Reactions

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Nocturnal homing in the tropical amblypygid \u3ci\u3ePhrynus pseudoparvulus\u3c/i\u3e (Class Arachnida, Order Amblypygi)

Arthropods are renowned for their navigational capabilities, with numerous examples known from insects and crustaceans. Early studies of amblypygids (Class Arachnida, Order Amblypygi) also suggest complex nocturnal navigation, despite their apparent lack of visual adaptations to the low-light conditions of a tropical understory. In a series of two studies, we use the tropical amblypygid, Phrynus pseudoparvulus, to assess their nocturnal homing ability. Our first experiment displaced and tracked resident and nonresident individuals. Resident individuals, displaced up to 4.5 m from their home refuges and released onto their home tree, were more likely to return to their previously occupied refuge than were nonresident individuals that were collected from trees outside the study area and released at the same locations. In a follow-up study, we displaced amblypygids longer distances (6–8.7 m) from their home trees and tracked them by telemetry. These individuals returned to home trees, typically within 1–3 nights, often via indirect paths. Taken together, our results provide evidence that P. pseudoparvulus are able to navigate home, often taking indirect routes, and can do so through a mechanism other than path integration

Polarization Transfer in Inelastic Proton Scattering from 12-C and 16-O

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440