Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172당신이 사용하는 게 아니라요?교과서 변경

Sanders 3rd Edition

Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels

문제 D.10

20장, 문제 D.10

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?

검증된 단계별 안내

Step 1: Understand the context of Denisovans as an archaic human group identified primarily from fossils found in Denisova Cave in Siberia, but whose genetic legacy appears in modern populations far from that location, such as Australians and Melanesians.

Step 2: Recognize that the presence of Denisovan DNA in distant populations suggests historical interbreeding events between Denisovans and the ancestors of these modern groups during their migration.

Step 3: Consider the migration routes of early modern humans out of Africa, which likely passed through Asia and could have overlapped geographically and temporally with Denisovan populations, allowing for gene flow.

Step 4: Explore the concept of gene flow and admixture, where interbreeding between distinct populations results in the transfer of genetic material, explaining how Denisovan DNA could be present in populations far from the original fossil site.

Step 5: Synthesize this information to conclude that the geographic differences can be reconciled by understanding that Denisovans had a wider range than the fossil record alone shows, and that their genetic influence spread through admixture with migrating modern humans across Asia.

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Ancient Human Migration

Ancient human migration refers to the movement of early human populations across different regions over time. Understanding migration routes helps explain how genetic material from groups like Denisovans spread far from their original locations, such as from Siberia to Southeast Asia and Oceania.

Interbreeding and Genetic Admixture

Interbreeding between distinct hominin groups, such as Denisovans and modern humans, led to genetic admixture. This process results in the presence of Denisovan DNA in modern populations, even if those populations live far from where Denisovan fossils were found.

Population Genetics and DNA Tracing

Population genetics studies the distribution of genetic variations within and between populations. By analyzing DNA sequences, scientists can trace ancestral relationships and migration patterns, revealing how Denisovan genetic markers appear in distant populations like Australians and Melanesians.