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Animation: Independent Assortment

by Pearson
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To understand the principle of independent assortment, let's consider one of Gregor Mendel's classic crosses. In this cross, Mendel mated a plant grown from a round, yellow pea to a plant grown from a wrinkled, green pea. The offspring of this cross appear in equal proportions of shape and color combinations. The wrinkled, green parent is homozygous for the recessive r and y alleles and produces only one gamete genotype. The round, yellow parent is heterozygous (Rr and Yy) for both genes and produces equal proportions of four gamete genotypes. The gametes fuse with each other in the cross to yield equal proportions of offspring genotypes. Note that in the gametes from the round, yellow parent, the dominant R allele is just as likely to be found with the dominant Y allele as it is to be found with the recessive y allele. In other words, the R and Y alleles behave independently of each other during gamete formation. Mendel referred to this independence as the principle of independent assortment. Today we know that independent assortment is explained by the independent alignment and segregation of nonhomologous chromosomes during meiosis.
To understand the principle of independent assortment, let's consider one of Gregor Mendel's classic crosses. In this cross, Mendel mated a plant grown from a round, yellow pea to a plant grown from a wrinkled, green pea. The offspring of this cross appear in equal proportions of shape and color combinations. The wrinkled, green parent is homozygous for the recessive r and y alleles and produces only one gamete genotype. The round, yellow parent is heterozygous (Rr and Yy) for both genes and produces equal proportions of four gamete genotypes. The gametes fuse with each other in the cross to yield equal proportions of offspring genotypes. Note that in the gametes from the round, yellow parent, the dominant R allele is just as likely to be found with the dominant Y allele as it is to be found with the recessive y allele. In other words, the R and Y alleles behave independently of each other during gamete formation. Mendel referred to this independence as the principle of independent assortment. Today we know that independent assortment is explained by the independent alignment and segregation of nonhomologous chromosomes during meiosis.