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- We say that crossing over is reciprocal. What does that mean for the products of crossing over.
- Explain how, if the chromatids of two homologous chromosomes crossover 100% of the time, it gives
a recombination frequency of 50%.
- If, given the genotype of the individual as A—B/a—b, we get 50% crossover, what should kinds of
gametes should be produced and in what ratios?
- Recombination frequencies = map distances meaning how far two genes on the same chromosome are apart. Explain Recombination frequency is related to how far two genes are apart.
- Use the crossover frequencies below to generate a map of ABCD and how far they are apart.
Gene Frequency of Crossover A-C 30% B-C 45% B-D 40% A-D 25%
6 Five Lysine-auxotrophic bacterial strains (1-5) have been identified. Each strain contains a single mutant gene. Supplements A, B, C, E, F are intermediates in the Lysine Biosynthesis Pathway.
Supplement D is Lysine. The “+” in the table indicates that the strain will grow if given that supplement, an “-” means lack of growth. List the order of supplements in the pathway from the first step to last
step.
- An AB/ab woman has a child with an ab/ab man what is the probability that their first child will be Ab? Given: a and b loci are 20 mu apart.
Parental A----B a----b
A. 40 % A—B
B. 40% a---b
C. 10% A—b
D. 10% a---B
- The R/r and S/s genes are linked and 10 map units apart. In the cross Rs/rS × rs/rs what percentage
of the progeny will be Rs/rs?
A. 5%
B. 10%
C. 25%
D. 40%
E. 45% *
11. In rabbits, spotted (En) is dominant to solid (en), while full color or agouti (C) is dominant to
chinchilla (cn). Rabbits that are heterozygous for both traits were crossed to solid, chinchilla
rabbits with the following results: 8 solid, chinchilla; 6 spotted, agouti; 45 solid, agouti; 41 spotted,
chinchilla
A. What is the arrangement of genes on chromosomes in the F1?
B. What is the distance between the genes?
- The table below shows crosses between various mutant flower strains (1-6)
How many complementation groups are there? What are the mutants in each group?
- Neurospora were mutagenized and Arginine auxotrophs were identified. The table below shows the mating of fungi from the different arginine mutant strains.
Mutant number 1 2 3 4 5 6
What are the complementation groups?
