BIOL 1090 Lecture Notes - Lecture 5: Punnett Square, Gamete, Zygosity
2 Nov 2017
School
Department
Course
Professor
Document Summary
Me(cid:374)del"s pri(cid:374)ciples are used to predict the outco(cid:373)es of crosses. Lecture 5 based on an exam question example. Had 3 genes, each have recessive and dominant alleles. These genes break down into 3 monohybrid crosses, determine expected genotypes by punnett squares. Punnet square (not a good method if have more than 3 heterozygous genes) Determining genetic outcome of crosses with 1 or 2 genes (ea with 2 alleles) 2n, n = number of genes, = number of gamete combinations. Alternate method for determining outcome of a genetic cross and is based on the principle of probability. Multiplicative rule: p(a) x p(b), probability that they occur together is the product of the individual probabilities of occurrence. Therefore, multiplying the fractions of the independent gene crossings together to get the total probability. Frequencies = p(dd or dd) x p(gg) x p(ww) Additive rule: probability that one or the another event occurs; p(a) + p(b)
