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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.
Answer
This option suggests that the origin of our species lies in Africa, where there would have been significant time for genetic variation to accumulate in mitochondrial DNA. Since mitochondrial DNA is passed down maternally, this explanation aligns with the observation that African populations exhibit the highest levels of genetic variation.
Step 2
B. mitochondrial DNA has a higher mutation rate in African environments.
Answer
While it's conceivable that environmental factors could influence mutation rates, there's not substantial evidence to suggest a consistently higher mutation rate of mitochondrial DNA specifically in Africa compared to other regions.
Step 3
C. gene flow occurred between Homo sapiens and other Homo species in Africa.
Answer
Gene flow can indeed affect genetic variation; however, it would more likely contribute to the mix of existing variations rather than being the main source of overall mitochondrial DNA variation in modern humans.
Step 4