Abstract.
The purpose of this lab experiment was to determine if allele frequencies and genotype frequencies remain the same or change from generation to generation. According to the law of segregation, when crossing two heterozygotes, the phenotypic ratio of offspring should be 3:1 (dominant to recessive). The Hardy Weinberg law states that the phenotypic ratios remain constant from generation to generation.
F2, F6, and F8 generation corn seeds were planted in a tray divided into three sections. The dominant allele, A, produces normal green plants and the recessive allele, a, produces white plants containing no chlorophyll (albino). Aa was then crossed with Aa. The offspring of that cross (F2) was crossed to itself to give the next generation (F3) and so on until conclusion at F8 generation. The allele that produced the albino plant was monitored. .
The results of the experiment showed that the albino allele, a, decreased from generation to generation. .
Introduction.
According to the law of segregation, when crossing two heterozygotes, the phenotypic ratio of offspring should be 3:1 (dominant to recessive). In order to get a F2 ratio of 3:1 (green to white) in corn seeds, two heterozygotes (Aa) with A being the dominant allele and a being the recessive allele, were crossed.
The Hardy Weinberg law states that phenotypic ratios remain constant from generation to generation. When taking this law into account one must make some assumptions. All genotypes must be equal in viability and fertility or the law is invalid. The allele and genotype frequencies will change if these assumptions are violated. These changes are represented by the theory of popular genetics equation: qt+1 = ptqt/pt2 + 2ptqt.
The pt and qt represent the frequencies of the dominant and recessive alleles respectively. The qt+1 in the equation is the recessive allele one generation later if the Hardy Weinberg law is violated.
