What is the term for differences in the gene composition among individuals within a population?

The term that describes the differences in gene composition among individuals within a population is "genetic variation." This concept is fundamental in genetics and evolution, as it refers to the diversity found in the genetic makeup of organisms. Genetic variation can arise from mutations, gene flow, and sexual reproduction, leading to different alleles for traits within a population.

This variation is crucial because it provides the raw material for natural selection to act upon, enabling populations to adapt to changing environments or pressures. Without genetic variation, a population may struggle to survive when faced with diseases, environmental changes, or other challenges.

The other terms are related but do not specifically refer to differences in gene composition among individuals. Gene drift, or genetic drift, refers to changes in allele frequency due to random sampling effects, particularly in small populations. Allele frequency measures how often a particular allele appears in a population, rather than the diversity itself. The gene pool encompasses all the genetic information within a breeding population, again, not specifically highlighting individual differences.