Genome-wide comparisons of populations worldwide show that within-population differences account for _____ genetic variation, while average differences between population are _____. Group of answer choices
The correct answer and explanation is:
Correct Answer:
Within-population differences account for most genetic variation, while average differences between populations are relatively small.
Explanation (approx. 300 words):
Genome-wide studies of human populations have revealed key insights into the distribution of genetic variation. A major finding, supported by research including that of geneticist Richard Lewontin in the 1970s and confirmed by modern genomics, is that the vast majority of human genetic diversity—about 85% to 90%—exists within populations, not between them. This means that if you compare two individuals from the same population (for example, two people from Kenya or Norway), they will show nearly as much genetic variation as two people selected from different populations around the globe.
In contrast, genetic differences between populations—such as between Europeans, Asians, or Africans—account for only about 10% to 15% of total human genetic variation. These between-group differences are statistically significant but relatively small in magnitude. They often reflect adaptation to local environments (such as skin color, lactose tolerance, or resistance to diseases like malaria) but do not justify the biological concept of race as a rigid category.
These findings have profound implications. Genetically, all humans are more alike than different. The small genetic variation between populations is insufficient to support the idea of distinct biological “races” in humans. Instead, the concept of race is largely a social construct without a consistent basis in human biology.
The genomic data also highlight the shared ancestry of all humans. Since Homo sapiens originated in Africa, genetic diversity is actually highest among African populations, who have had the most time to accumulate genetic differences. Populations outside Africa represent subgroups that migrated relatively recently in evolutionary terms and carry only a portion of that original diversity.
In summary, while some genetic differences between populations exist, most genetic variation is found within populations, reinforcing the unity and interconnectedness of all human beings.