WHAT IS INDEPENDENT ASSORTMENT???????!!!!!!!!!!!!?

Mendel suggested that the distribution of one pair of alleles into gametes has no influence on the distribution of any other pairs of alleles. Today, we know this is NOT true, since linked alleles CAN affect each other. Mendel happened to choose traits that were NOT LINKED, so he didn't realize his error...

Principle of Independent Assortment: The principle of independent assortment says that when gametes are formed in diploid organisms, the segregation of each gene pair does not affect the segregation of other gene pairs as long as the gene pairs are on separate chromosomes. For example suppose an organism has the following genotype: AaBb. Aa represents a gene pair and Bb represents the other gene pair. By the principle of segregation half the gametes have the 'A' allele and the other half have the a 'a' allele. But half the gametes also have the 'B' allele and half the gametes have the 'b' allele. What Gregor Mendel realized was that for both gene pairs the fraction of gametes getting alleles A and B or in other words having genotype 'AB' (one gene from each gene pair) is 1/2 * 1/2 = 1/4. In other words the gene pairs are behaving independently from one another. So our parent with genotype AaBb produces the following gametes and in the following proportions: Gamete genotype Expected proportion AB 1/4 Ab 1/4 AB 1/4 AB 1/4 This works because when the gene pairs are on separate chromosomes, that is unlinked then we can use the multiplication rule for independent probabilities to figure out the expected proportion of gametes. In other words the proportion of gametes produced by the AaBb individual which have the genotype 'AB' is The proportion of gametes with the 'A' allele times the proportion of gametes with the 'B' allele, or 1/2 * 1/2 = 1/4. form the above exapmle its clear that independent assortment leads to genetic variation.

According to this law, the alleles are independently separate for the gamete formation. This law is proposed by Mendel.