Final answer:
The statement is true; alleles segregate during gamete formation as homologous chromosomes separate during anaphase I of meiosis I, resulting in gametes with a single allele for each gene.
Step-by-step explanation:
The statement that alleles segregate from each other during gamete formation when homologous chromosomes separate at anaphase I is true. During the process of meiosis, specifically at anaphase I of meiosis I, the homologous chromosomes, each carrying different alleles, are pulled to opposite poles of the cell, ensuring that each gamete receives only one allele for each gene. This is known as Mendel's first law, the Law of Segregation.
In the subsequent phase of meiosis II, sister chromatids separate, leading to the production of four unique gametes with haploid chromosomes, further contributing to genetic diversity.