Final answer:
Mendel's Law of Segregation explains how alleles for each gene segregate during gamete formation, resulting in offspring inheriting one allele per gene from each parent, as seen in the predictable 3:1 ratio for dominant-recessive traits. Meiosis is the biological process underlying this genetic principle, and Punnett squares utilize it for genetic predictions.
Step-by-step explanation:
The concept you are inquiring about refers to Mendel's Law of Segregation, which is a fundamental principle of genetics. This law explains how alleles (the different versions of a gene) are separated during the formation of gametes (sex cells like eggs and sperm). Each parent contributes one allele for each gene, and during fertilization, these alleles recombine randomly to form the genetic makeup of the offspring. For example, in the case of pea plants, which Gregor Mendel originally studied, this law predicts the 3:1 phenotypic ratio observed in monohybrid crosses. The physical process that underlies this law is the first division of meiosis, during which homologous chromosomes segregate into different gametes, ensuring that each gamete carries only one allele for each trait. Furthermore, the Punnett square is a tool that applies the principle of the equal segregation of alleles to predict the genotypes and phenotypes of offspring from parents with known genotypes. The law of segregation is critical for understanding how certain traits are inherited and expresses why genetic variation is observed in populations.