22. Evolutionary Genetics

Which of the following structures on a phylogenetic tree represents the evolutionary connections between organisms?

Which principle is NOT used to construct a phylogenetic tree?

Why might mitochondrial, Y chromosome, and autosomal DNA provide different perspectives on our evolutionary past, for example, with respect to our relationship with Neanderthals?

What insights have analyses of human mitochondrial DNA provided into our recent evolutionary past?

What lines of evidence support the hypothesis that modern humans evolved in Africa and then subsequently migrated throughout the globe?

Discuss how both gains and losses of regulatory elements may lead to human-specific traits.

How do copy-number variants arise? Do they account for more polymorphism than SNPs within the human population?

Consider possible societal and ethical dilemmas that might arise if we currently shared the planet with another hominin.

Carl Linnaeus, the 18th-century botanist who laid the foundation for the modern system of taxonomic nomenclature, placed chimpanzees and humans in the same genus. Discuss the merits of this classification.

What must be assumed in order to validate the answers in Problem 7?

Describe how selection at a locus can result in a loss of polymorphism surrounding the locus.

How can ancient DNA provide insight into past migrations that analyses of extant human genomes fail to uncover?

Denisovans are known from bones found in Denisova Cave in the Altai Mountains in Siberia, but traces of their DNA are found in Australians and Melanesians, whose ancestors likely migrated across Asia much farther to the south. How can these geographic differences be reconciled?

In Island Melanesia and Polynesia, most mtDNA haplotypes are of Asian ancestry, whereas Y chromosome haplotypes are predominantly New Guinean. Provide a hypothesis for this sex-biased distribution.

A 9-bp deletion in the mitochondrial genome between the gene for cytochrome oxidase subunit II and the gene for tRNAᴸʸˢ is a common polymorphism among Polynesians and also in a population of Taiwanese natives. The frequency of the polymorphism varies between populations: The highest frequency is seen in the Maoris of New Zealand (98%), lower levels are seen in eastern Polynesia (80%) and western Polynesia (89%), and the lowest level is seen in the Taiwanese population. What do these frequencies tell us about the settlement of the Pacific by the ancestors of the present-day Polynesians?