krown Posted August 30, 2016 Share Posted August 30, 2016 I need help in a genetics problem that is confusing me, if anyone could pls, . Plant three-way cross: (A x B) x C . (A x B ), A and B differ by genes at 5 loci . Cross the result of Ax B with homozygous line C . C does not increase the number of segregating loci and F 1 produces all seeds needed for representing the A/B//C progeny, F2 population does not need to be considered Question 1: How many F1 seed will you need for A/B//C (F2 pop does not need to be considered for question 1 ? Question 2: Suppose now each F1 plant produces 300 F2 seeds, how many F1 seed would we need to to A/B//C completely represent the population ? Question 3: If we assume now that A and B differ at 5 loci and that C increases the dif loci by 2 (A and B were homozygous and similar at these 2 loci), also assume that each F1 seed produces 300F2 seeds, consider the F2 population and define how many F1 seed we would need to properly represent C/D//F. obs: what confuses me is that when we calculate above cases for a single homozygous cross, number of F1 seeds to represent A x B is only 1 seed (one gamete from each parent), and in the three way cross would be (#2 elevated to the # of different loci). Also that the number of needed to properly represent the population for a single way cross is (#3 elevated to the # of different loci), because selfing F1 Aa we would have 1AA, 2Aa, 1aa (3 genotypes). But when we assume these parameters for a three way corn cross it confuses me. Thanks ! krown Link to comment Share on other sites More sharing options...
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