Segregation. The Principle of Segregation describes how pairs of gene variants are separated into reproductive cells. <span>The segregation of gene variants, called alleles, and their corresponding traits was first observed by Gregor Mendel in 1865. Mendel was studying genetics by performing mating crosses in pea plants. He crossed two heterozygous pea plants, which means that each plant had two different alleles at a particular genetic position. He discovered that the traits in the offspring of his crosses did not always match the traits in the parental plants. This meant that the pair of alleles encoding the traits in each parental plant had separated or segregated from one another during the formation of the reproductive cells. From his data, Mendel formulated the Principle of Segregation. We now know that the segregation of genes occurs during meiosis in eukaryotes, which is a process that produces reproductive cells called gametes.</span>
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The ABO blood group classification is based on antigens on red blood cells and antibodies found in blood plasma.</span>Blood type A has antigen A on the red blood cells and anti - B antibodies in the blood.Blood type B has antigen B on the red blood cells and anti - A antibodies in the blood.Blood type AB has both antigen A and B on the red blood cells but has no anti-A nor anti - B antibodies in the blood<span>Blood type O has no antigen on the red blood cells and has both anti -A and anti B antibodies in the blood.</span>
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