Which Statement Summarizes the Law of Segregation

Equal Segregation of Alleles

Observing that truthful-breeding pea plants with contrasting traits gave rise to F₁
generations that all expressed the dominant trait and F_two
generations that expressed the ascendant and recessive traits in a three:1 ratio, Mendel proposed the law of segregation. The police of segregation states that each individual that is a diploid has a pair of alleles (copy) for a detail trait. Each parent passes an allele at random to their offspring resulting in a diploid organism. The allele that contains the dominant trait determines the phenotype of the offspring. In essence, the law states that copies of genes separate or segregate and so that each gamete receives only one allele.

For the F₂
generation of a monohybrid cross, the following three possible combinations of genotypes could result: homozygous dominant, heterozygous, or homozygous recessive. Because heterozygotes could ascend from two different pathways (receiving 1 dominant and one recessive allele from either parent), and because heterozygotes and homozygous dominant individuals are phenotypically identical, the law supports Mendel’s observed three:one phenotypic ratio. The equal segregation of alleles is the reason we tin can apply the Punnett square to accurately predict the offspring of parents with known genotypes.

The concrete basis of Mendel’southward police force of segregation is the get-go sectionalisation of meiosis in which the homologous chromosomes with their different versions of each cistron are segregated into daughter nuclei. The behavior of homologous chromosomes during meiosis can account for the segregation of the alleles at each genetic locus to different gametes. As chromosomes separate into unlike gametes during meiosis, the ii different alleles for a particular factor also segregate so that each gamete acquires one of the two alleles. In Mendel’s experiments, the segregation and the independent assortment during meiosis in the F1 generation requite rise to the F2 phenotypic ratios observed by Mendel. The role of the meiotic segregation of chromosomes in sexual reproduction was not understood past the scientific community during Mendel’due south lifetime.

Key Points

• Each gamete acquires ane of the ii alleles as chromosomes separate into different gametes during meiosis.
• Heterozygotes, which posess 1 dominant and one recessive allele, can receive each allele from either parent and volition look identical to homozygous dominant individuals; the Law of Segregation supports Mendel’s observed iii:1 phenotypic ratio.
• Mendel proposed the Law of Segregation after observing that pea plants with 2 different traits produced offspring that all expressed the ascendant trait, but the following generation expressed the dominant and recessive traits in a iii:1 ratio.

Key Terms

• law of segregation: a diploid individual possesses a pair of alleles for any particular trait and each parent passes i of these randomly to its offspring