Hairs on the dorsum are banded, and the ventral hairs are light colored. Throughout most of their range, pocket mice have sandy dorsal coats with white underbellies. Although there are no direct studies of pocket mice predators, it is well established that they are preyed upon by owls, snakes, and mammalian carnivores (Hoekstra and Nachman, 2005). Young mice are born naked and typically attain their first coat at two to three weeks (Hoekstra and Nachman, 2005) the first coat is generally thinner and duller than the adult coats. intermedius are nocturnal mammals and decrease activity from November through February. Typically, they range from southern Utah through Arizona, New Mexico, and Texas (Hoekstra and Nachman, 2005). Sex and Evolution (Senior at low elevations in the southwestern deserts of North America. Pocket mice inhabit rocky areas and desert scrub _ *This author wrote the paper for Biology 482: Seminar) taught by Dr. Pocket mice are the primary model organism for Hoesktra’s lab. Loeb Associate Professor of Biology in the Department of Organismic and Evolutionary Biology and the Curator of Mammals at the Museum of Comparative Zoology (Hoekstra home page). Just recently, she moved to Harvard University, where she is the John L. In 2003, she became an Assistant Professor at the University of California San Diego. Hoekstra then moved to the University of Arizona as a NIH Postdoctoral Fellow where she studied the genetic basis of adaptive melanism in pocket mice. in Zoology in 2000 as a Howard Hughes Predoctoral Fellow at the University of Washington. It is suggested that phenotypic variation is due to natural selection and that variation in multiple regions is caused by a few interacting genes. The main questions that this story brings to focus are: 1) is this coat color variation a consequence of natural selection and 2) if there is variation in more than one area or region, are these caused by the same gene of not? This paper will explore coat coloration in pocket mice based on the work of evolutionary biologist Hopi Hoekstra. Genetics seem to play a role in that their coat color typically matches the color of the rocks on which they live.(Hoekstra and Nachman, 2003 Hoekstra, Drumm, and Nachman, 2004). Rock pocket mice provide a useful system for studying the genetics of adaptation.
This color polymorphism is a presumed adaptation to avoid predation from avian and mammalian predators (Nachman, Hoekstra, and D’Agostino, 2005).
Furthermore, the pocket mice on volcanic lava with dark coats do not have banded hairs, whereas mice from nearby light-colored granitic rocks have light coats that do have banded hairs. Several studies have found that most light-colored mice live on light-colored rocks, but in several geographic regions, they are melanic (black or brown) and live on dark-colored basalt lava (Hoekstra and Nachman, 2003 Hoekstra, Drumm, and Nachman, 2004). intermedius coat color matched the color of the rocks on which the mice live (Nachman, Hoekstra, and D’Agostino, 2005). Many studies have found coat color variation in the rock pocket mouse in deserts of the southwestern states (Nachman, Hoekstra, and D’Agostino, 2005). The rock pocket mouse is one of the most studied models for phenotypic color variation.
Examples of intraspecific color variation in rodents include the canyon mouse (Peromyscus crunitus), the deer field mouse (Peromyscus maniculatus), the old-field mouse (Peromyscus polionotus), and the rock pocket mouse (Chaetodius intermedius) (Hoekstra and Nachman, 2005). 6, March 2010, Lake Forest College Review Article Melanic Coat Color Variation in Rock Pocket Mice (Chaetodius intermedius) Laura Thilgen* Department of Biology Lake Forest College Lake Forest, Illinois 60045 Coat color variation in small mammals is a classic example of phenotypic variation in response to selection in different environments (Hoekstra and Nachman, 2005) many species closely match the color of the substrate in which they live.
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