The human melanocortin 1 receptor gene (MC1R) plays a major role in producing eumelanin, a black-brown pigment that helps determine hair color and skin color. Jonathan Rees and several colleagues (J. L. Rees et al., Am. J. Human Genet. 66(2000): 1351–1361) studied multiple MC1R alleles in African and European populations. Although this research found several MC1R alleles in African populations, MC1R alleles that decrease the production of eumelanin were rare. In contrast, several alleles decreasing eumelanin production were found in European populations. How can these results be explained by natural selection?

Draw a separate hypothetical pedigree identifying the inbred individuals and the inbreeding pathways for each of the following inbreeding coefficients:F=4(1/2)⁶

Draw a separate hypothetical pedigree identifying the inbred individuals and the inbreeding pathways for each of the following inbreeding coefficients:F=2(1/2)⁵

Draw a separate hypothetical pedigree identifying the inbred individuals and the inbreeding pathways for each of the following inbreeding coefficients:F=4(1/2)⁸

Draw a separate hypothetical pedigree identifying the inbred individuals and the inbreeding pathways for each of the following inbreeding coefficients:F=2(1/2)⁷

Achromatopsia is a rare autosomal recessive form of complete color blindness that affects about 1 in 20,000 people in most populations. People with this disorder see only in black and white and have extreme sensitivity to light and poor visual acuity. On Pingelap Island, one of a cluster of coral atoll islands in the Federated States of Micronesia, approximately 10% of the 3000 indigenous Pingelapese inhabitants have achromatopsia.Achromatopsia was first recorded on Pingelap in the mid-1800s, about four generations after a typhoon devastated Pingelap and reduced the island population to about 20 people. All Pingelapese with achromatopsia trace their ancestry to one male who was one of the 20 typhoon survivors. Provide a genetic explanation for the origin of achromatopsia on Pingelap, and explain the most likely evolutionary model for the high frequency there of achromatopsia.

New allopolyploid plant species can arise by hybridization between two species. If hybridization occurs between a diploid plant species with 2n = 14 and a second diploid species with 2n = 22, the new allopolyploid would have 36 chromosomes.What pattern of speciation is illustrated by the development of the allopolyploid species?

New allopolyploid plant species can arise by hybridization between two species. If hybridization occurs between a diploid plant species with 2n = 14 and a second diploid species with 2n = 22, the new allopolyploid would have 36 chromosomes.What type of isolation mechanism is most likely to prevent hybridization between the allopolyploid and the diploid species?

New allopolyploid plant species can arise by hybridization between two species. If hybridization occurs between a diploid plant species with 2n = 14 and a second diploid species with 2n = 22, the new allopolyploid would have 36 chromosomes.Is it likely that sexual reproduction between the allopolyploid species and either of its diploid ancestors would yield fertile progeny? Why or why not?