*If two genes are linked on a chromosome and over 50 map units apart, in theory you will not recover more than 50% recombinants, which is the same as independent assortment (genes on two different chromosomes). Using diagrams, show why this is so.

In the fruit fly, dumpy wings (d) and purple eyes (p) are encoded by mutant alleles that are recessive to those that produce wild type traits; long wings (d+) and red eyes (p+). These two genes are on the same chromosome. In a particular lab, two researchers Walt and Jesse crossed a fly homozygous for dumpy wings and purple eyes with a fly homozygous for the wild type traits. The F1 progeny, which had long wings and red eyes, was then crossed with flies that had dumpy wings and purple eyes. Unfortunately, the progeny of this cross somehow escaped. To prevent their other projects from contamination, they decided to spend an exceptionally boring hour in the lab catching and counting the progeny and found the following:   long wings, red eyes – 482 dumpy wings, purple eyes – 473 long wings, purple eyes – 23 dumpy wings, red eyes - 22   What is the genetic distance between these two loci? a. 4.5 cM b. 55 cM c. 45 cM d. 49.5 cM  e. 4.7 cM

Here is a strawberry karyotype - ignore the different colours. How many chromosomes are shown in the figure? What is the ploidy of this type of strawberry? How many alleles could an individual strawberry have at each locus? Finally during the G2 stage of cell division, how many double helixes would be in this picture if you drew them over the chromosomes? Many domesticated plants are polyploid - give one possible reason why this might be the case, with a focus on using genetic principles to reason it out (i.e., you don't have to be right per se, you have to build an argument based on what you've already learned).

Given the experimental set up below, and knowing the genes for stalked eyes (st) and black bodies (b) are on the same chromosome and recessive to wild type (un-stalked eyes and light body).  F2= a=489, b=56, c=497, d=49 A)  How many recombinant animals are in the F2 generation? B) ( How far apart, (as both a % recombination and in map units) are the stalk eyed and black bodied genes on this chromosome?