BioSc 231 General Genetics Exam 3 Name __________________________________Multiple Choice. (2 points each)__C__ Recombination frequencies ___A. are the same for all genes.B. arise from specific genetic exchange.C. are the same for cis and trans heterozygotes.D. decrease with distance.__ B__ A plant of genotype C/C;d/d is crossed to c/c;D/D and an F1 testcrossed to c/c;d/d. If the genes are linked and 40 map units apart, the percentage of c/c;d/d recombinants will beA. 10%B. 20%C. 30%D. 40%E. 50%__ C__ The maximum recombination frequency between two genes isA. 100%B. 80%C. 50%D. 10%E. 1%__ B__ In Drosophila, the two genes w and sn are X-linked and 25 map units apart. A female fly of genotype w+ sn+/w sn is crossed toa male from a wild-type line. What percentage of male progeny will be w+ sn?A. 0B. 12.5%C. 25%D. 37.5%E. 50%__ C__ The maize genes sh and bz are linked, 40 map units apart. If a plant sh+ bz/sh bz+ is selfed, what proportion of the progeny willbe sh bz/sh bz?A. 0.04B. 0.10C. 0.20D. 0.40__ A__ In maize, two plants that are both heterozygous for the recessive alleles a and b are crossed. What frequency of double-mutantprogeny will appear if a and b are 7.2 map units apart and both parents carry a and b in trans?A. 0.036B. 0.0625C. 0.001296D. 0.005184E. 0.072 __ D__ In crossing overA. Genetic exchange occurs before chromosome replicationB. The probability of its occurrence decreases with increasing distance between the genes exchangedC. Occurs between two loci very close togetherD. The reciprocal exchange between homologous chromosomes is random__ A__ The F, G and H loci are linked in the order written. There are 30 map units between F and G, and 30 map units between G and H. If a plant F G h/f g H is testcrossed, what proportion of the progeny plants will be f g h/f g h if there is complete interference?A. 0.15B. 0.21C. 0.245D. 0.3E. 0.7__ C__ Out of 800 progeny of a three-point testcross there were 24 double crossover recombinants, whereas 30 had been expected on the basis of no interference. The interference isA. 0.05B. 0.10C. 0.20D. 0.50E. 0.80__ B__ In a four-point testcross the number of phenotypic classes of progeny expected isA. 4B. 8C. 16D. 32E. depends on the gene linkage of the tetrahybrid__ B__ In a cross of two yeast strains of genotypes c+ a+ X c a the progeny were42 c+ a+46 c a5 c+ a7 c a+The frequency of recombination isA. 11%B. 12%C. 24%D. 50%E. 76%__ D__ Two genes with a 50% recombination frequency areA. Present on homologous chromosomesB. Located close byC. LinkedD. Far apart on a single chromosome__ E__ In testcross experiments, the frequency of recombination between genes a and b is 0.3; between b and c, 0.2; between c and d, 0.1; between a and c, 0.5; and between b and d, 0.3. What is the order of the three genes?A. c-b-d-aB. d-c-a-bC. a-d-c-bD. b-a-c-dE. a-b-c-d__ A__ Three-point test crossesA. Detect double crossing over eventsB. Require heterozygous gametesC. Cannot determine gene order on a chromosomeD. Determine goodness of fit__ B__ Genes ho and dp are 9.0 map units apart, and genes dp and da are 26.3 map units apart. What is the probability of a double crossover in these regions?A. 1.3%B. 2.3%C. 3.4%D. 4.5%E. 5.6%__ A__ In Drosophila, the genes r and s are linked. Flies of genotype r+ s+/ r+ s+ and r s/ r s are crossed and an F1 obtained. The F1 allele arrangement is calledA. cisB. transC. recombinantD. complementaryE. crossover__ C__ The Drosophila genes for white eyes (w), tan body (t) and vestigial wings (vg) lie at map positions 2, 22, and 52 respectively. Out of 500 progeny, 21 exhibited double crossovers. What is the degree of interference?A. 0.10B. 0.20C. 0.30D. 0.40__ A__ One Drosophila genotype P m/P m is crossed with another genotype p m/p m. If the genes are closely linked A. All progeny will be phenotypically PmB. All progeny will be phenotypically pmC. 50% of the progeny will be phenotypically Pm and 50% phenotypically pmD. None of the above__ B__ A plant of genotype C/C; D/D is crossed to c/c; d/d and an F1 testcrossed to c/c;d/d. If the genes are unlinked, the percentage of c/c;d/d recombinants will beA. 10%B. 25%C. 30%D. 40%E. 50%__ D__ Which of the following statements is true regarding recombination between genes on homologous chromosomes?A. Equivalent ratios (1:1:1:1) are found in progeny from homozygous dihybrid crossesB. Recombination frequencies are greater than 50%C. 25% of each genotype will appear among the progeny from dihybrid crossesD. Exchange of the middle pair of alleles occurs in double crossoversProblems (variable points each)Two-point testcrosses revealed the following map results:am___________pm 23 map unitspm___________nn 16 map unitsA. Draw the two possible maps for these loci. (2)am 23 pm 16 nn or am 7 nn 16 pmB. What cross would resolve the two possible maps and what are the possible outcomes of that cross? (1)A two-point testcross to map the distance between am and nn. If the first map is correct the distance would be 39 mu and if the second map is correct the distance would be 7 muYou could also do a three factor test cross and low recombination freq. would indicate which gene is in the middle.Consider a fully heterozygous flowering plant with normal blue flowers and round seeds. This plant, when crossed with one that has red flowers and oval seeds, results in the following progeny:91 blue, round94 red, round93 blue, oval92 red, ovalA. What is the recombination frequency? (2)50%B. Are these genes linked? (1)NOWhat gametes are produced by an individual with the genotype kL/Kl if the genes are A) linked (no crossing over) and B) unlinked? (2)Linked - kL and Kl unlinked - kL, kl, KL, KlSeveral testcrosses have revealed the rate of recombination for the following genes:k-m 0.06k-l 0.08l-m 0.13A. What is the order of the three genes? (2)l - k - mB. Why is the frequency of recombination between the two closest pairs of genes not equal to the recombination rate betweenthe two genes farthest apart? (1)Double crossover events lead to reduced recombination frequency between the two outside genes.An organism heterozygous for three genes AaBbCc was mated to a homozygote aabbcc, resulting in the progeny distribution below.ABC 327aBC 44AbC 30ABc 3 abC 4aBc 45Abc 28abc 319-----800Determine the gene order (1) and calculate recombination frequencies between each gene (3) and interference. (1)Gene Order - A - C - BRecombination frequency - A - C = 9.8%C - B = 10.2%A - B =