The highest level of genetic variation in mitochondrial DNA in modern-day humans occurs in African populations - VCE - SSCE Biology - Question 10 - 2008 - Paper 1
Question 10
The highest level of genetic variation in mitochondrial DNA in modern-day humans occurs in African populations.
The most likely explanation is that
A. Homo sapiens... show full transcript
Worked Solution & Example Answer:The highest level of genetic variation in mitochondrial DNA in modern-day humans occurs in African populations - VCE - SSCE Biology - Question 10 - 2008 - Paper 1
Step 1
A. Homo sapiens evolved in Africa.
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Answer
This explanation is supported by the Out of Africa theory, which suggests that modern humans originated in Africa and then migrated to other parts of the world. This migration would result in African populations retaining a higher level of genetic variation since they have had longer evolution times without the bottleneck effect seen in other regions.
Step 2
B. mitochondrial DNA has a higher mutation rate in African environments.
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While mitochondrial DNA mutation rates can vary, there is no substantial evidence that these rates are significantly higher in African environments than in others. This option does not adequately explain the observed genetic variation.
Step 3
C. gene flow occurred between Homo sapiens and other Homo species in Africa.
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Gene flow can contribute to genetic variation, but there is limited direct evidence supporting significant interbreeding within Africa as a primary factor for current levels of mitochondrial DNA variation.
Step 4
D. natural selection does not operate on mitochondrial DNA in African environments.
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This statement is misleading as natural selection can influence mitochondrial DNA, particularly in response to environmental pressures. Thus, this explanation is not accurate.
