The statement that humans share a quantifiable average percentage of genes and alleles is a fundamental biological fact reflecting population genetics and the high degree of genetic similarity among all humans, making formal citation unnecessary.
The claim is a foundational, trivially observable fact within genetics—all humans share the vast majority of their genome and allele types, with precise percentages routinely quantified in population genetics and anthropology (e.g., sharing approximately 99.9% of DNA sequence). Per the instructions, trivial statements or those true by definition/direct observation are classified as COMMON_KNOWLEDGE, requiring no citation or paper assignment.