The Genetic Basis of Adaptive Melanism on Pocket Mice Essay examples --

Introduction Whats the problem? Examples of animals adapting to the environment have been known as far back as the case of the fatal peppered moths of England in the mid-1800s. In that case, entire populations of the black peppered moths were observed to change color in response to changes in their environment. More recently, bacteria have been known to progress resistance to antibiotic drugs, insects have developed various forms of resistance to insecticide, and plants have adapted to accommodate higher levels of heavy metals in the soil and water. The problem is that it is delicate to locate the genes that stimulate adaptation for three reasons 1. Traits must be identified based on how they affect fitness and their ecological relevance. In other words, we pauperization to find a trait that clearly makes a difference in whether or not the animal survives. 2. It is challenging to analyze phenotypes when there is little breeding known about genes. With the moths, nobody knows which of the moths genes are responsible for the changes in color, so a genetic analysis is extremely difficult to do. 3. Most fitness-related traits are a mixture of many genes. This makes it hard to pin down the adaptations as a result of the actions of one gene. So where do the mice come in? Dr. Nachmans research explores the federation between genotype and coat color in four populations of rock pocket mice. Rock pocket mice live in rocky habitats in the southwest U.S. and northern Mexico. In the 1930s, classical studies revealed that there was a close correlation between the color of a mouses coat, and the color of the rocks the mouse lived on. Light-colored mice... ...is mice, the alleles did not show up to be responsible for any changes in coat color. The similarity between coat color of the dark mice at Pinacate and the dark mice at Armendaris is probably referable to convergent evolution. The Armendaris mice proba bly evolved the same adaptation (dark coat color) through a separate genetic mechanism. An interesting research project might be to check off the genetic basis of adaptation in the Armendaris population, and make comparisons. Any such results would be enormously useful in showing how evolution affects individual genes. ReferencesNachman, Michael W. try for E. Hoekstra, Susan L. DAgostino. The genetic basis of adaptive melanism in pocket mice. www.pnas.org/cgi/doi/10.1073/pnas.0431157100. Feb. 26, 2003.Purves,William K., et al. Life The Science of Biology Sixth Edition. Massachusetts Sinauer Assoicates, Inc. 2001.