[Campbell Biology P.510] Which of the following statements about genetic variation within th... | Practice Question

Which of the following statements about genetic variation within the human species, as described in the text, is ACCURATE?

  • A: Single nucleotide polymorphisms (SNPs) are considered genetic variations if they are found in less than 1% of the population.
  • B: Copy-number variants (CNVs) are less common than SNPs and have been found in about 1% of human genes.
  • C: Human DNA variation is relatively small compared to other species, largely due to the species' short evolutionary history.
  • D: SNPs are typically detected by analyzing chromosomal regions for inversions, deletions, and duplications.

Explanation

The passage states, "Because the history of the human species is so short—probably about 200,000 years—the amount of DNA variation among humans is small compared to that of many other species." This directly supports option C. Option A is incorrect as SNPs are defined for variations in at least 1% of the population. Option B is incorrect; CNVs are widespread and can involve a significant percentage 13% of genes, not 1%. Option D is incorrect; SNPs are detected by DNA sequencing, not by analyzing for larger chromosomal rearrangements.