Genetics Essay Example | Topics and Well Written Essays - 1000 words

Genetics - Essay Example If the F1 generation is further paired among itself by a yet another monohybrid cross than an F2 generation of plants will be produced. The expected phenotype of F2 generation would be 75% tall plants and 25% short plants. In F2 generation 25% of plants would be tall but would be homozygous for their trait of tallness. Another 50% of plants would also be tall but would be heterozygous for their trait of tallness while the remaining 25% of would be short and would be recessive for their trait. Dihybrid cross: A dihybrid cross is a cross between two individuals that involves two pairs of contrasting characteristics. If two plants that are pure bred (homozygous) for two contrasting traits for example one plant that is tall and produce yellow seeds (both dominant traits) and the other plant that is short and produces green seeds (both recessive traits) are crossed with other, than the F1 generation produced would be all heterozygous for both characteristics. But only dominant trait would appear in the phenotype of F1 generation and all plants of this generation would appear tall and would produce yellow seeds. If the members of this F1 generation are further crossed with each other than an F2 generation would produced which would have different types of plants: tall plants producing yellow seeds, tall plants producing green seeds, short plants producing yellow seeds, short plants producing green seeds in a ratio of 9:3:3:1 b) If a boar that is homozygous for lop ears and spotted skin is sow that is homozygous for pricked ears and unspotted skin than the F1 generation produced will all have pricked ear and spotted skin, as these two traits are dominant. The genotype of F1 generation would be PpSs. (Key: P= pricked ears, p=lop ears, S=spotted skin, s-unspotted skin). However the phenotype and genotype of F2 generation produced is shown as follows The Punnett Square