Final answer:
Mendel's law of independent assortment, which refers to the segregation of alleles during the formation of gametes, has its physical basis in the random arrangement of chromosomes during meiosis I. However, when genes are close on the same chromosome, they tend to be inherited together, violating this law. Recombination, which exchanges genetic material on homologous chromosomes, can allow these genes to assort independently.
Step-by-step explanation:
Mendel's law of independent assortment refers to the phenomenon where the alleles of different genes segregate, or assort, independently of each other during the formation of gametes. This law has its physical basis in the random arrangement of chromosomes on the metaphase plate in meiosis I (Option A). During this stage, different homologous pairs line up in random orientations. Each gamete can contain any combination of paternal and maternal chromosomes (and therefore the genes on them) because the orientation of tetrads on the metaphase plane is random.
However, it's important to note, as per Mendel's law of independent assortment, this refers to genes, not chromosomes, as a single chromosome may carry more than 1,000 genes.
When genes are located in close proximity on the same chromosome, their alleles tend to be inherited together. This results in offspring ratios that violate Mendel's law of independent assortment. However, recombination serves to exchange genetic material on homologous chromosomes such that maternal and paternal alleles may be recombined on the same chromosome. Therefore, genes that are far apart on the same chromosome are likely to still assort independently because of recombination events that occurred in the intervening chromosomal space.
Learn more about Mendel's law of independent assortment