Drosophila mutant lines are used: vestigial (vg) makes wings short and ebony (e)

Question

Drosophila mutant lines are used: vestigial (vg) makes wings short and ebony (e) makes body black Wild type wings are long and wild type body is gray. Both, vg and e mutations are recessive, autosomal and the two genes are not linked. A true breeding vestigial fly is crossed with a true breeding ebony fly. The expected F_1 phenotypic ratio is as follows: a) 3/4 vestigial: 1/4 ebony b) 1/2 vestigial, ebony: 1/2 wild type c) 3/4 Wild type: 1/4 vestigial, ebony d) all wild type c) all vestigial, ebony Gametes produced by the F_1 individuals are as follows: a) 1 vg e: 1 vg e^+: 1 vg + e: 1 vg + e + b) 1 vg vg: 1 e e: 1 vg+ e+: 1 vg e c) 1 vg: 1 e: 1 vg^+: 1 e^+ d) 1 +: 1 vermillion: 1 ebony e) none of the above The F_2 phenotypic ratio is as follows: a) 1 wild type: 1 vestigial: 1 ebony: 1 vestigial, ebony b) 3 vestigial: 1 ebony c) 9 wild type: 3 vestigial: 3 ebony: 1 vestigial, ebony d) 9 vestigial, ebony: 3 vestigial: 3 ebony: 1 wild type e) 1 female ebony: 1 male ebony: 1 female vestigial A cross between the black and ton strains of Sordaria produced 100 asci. Among those, 62 asci contained recombinant spore arrangement. The distance of the tan locus to the centromere is therefore___. a) 93 m.u. b) 62 m.u. c) 31 m.u. d) 15 m.u. e) 6.2 m.u. Corresponding figure illustrates results of a cross between block and ton strains of Sordaria. Which of the asci (1-4) have the recombinant spore arrangement? a) 1.2, 3, 4, b) 1, 2, 3 c) 2, 3, 4 d) 1, 2, 4 e) 2, 4 A cross between block and ton strains of Sordaria results in some parental arrangements of spores in the asci. This is likely due to the fact that there was no crossing over occurring in the genetic region of interest during meiosis. a) true b) false A cross between the between the block and ton strains of Sordaria was set up. The original arrangement of alleles is t_1 t_2 b_3 b_4. Crossing over occurs between chromatids t_1 and b_3. The ascus resulting from this crossing over will contain the following score pattern: a) bbbbtttt b) bbttttbb c) ttbbttbb d) ttbbbbtt e) tbtb The segregation of alleles affecting ascospore color In Sordaria can be observed directly in the ascus by looking at the ascospore phenotypes, without any further genetic testing. This is due to the fact that Sordaria___ a) zygote is haploid b) is a fungus c) ascospores are diploid d) ascospores are haploid e) fan locus is X-linked Draw the chromosome arrangement at metaphase I and metaphase II formed during spermatogenesis of an animal cell with 2n=2. Clearly label all components, including the spindle. Explain how you grew Drosophila in a lab and how you set up the crosses

Explanation / Answer

Cross between true breeding vestigial and true breeding ebony.

Let vg be the allele for vestigial and vg+ for long wings

e be the allele for ebony and e+ allele for gray

Vestigial gray body X long wings black(ebony)

vgvge+e+ X vg+vg+ee

F1 offsprings vg+vg e+e long wings gray body

All will be wild type

2) Gametes of F1 generation are

1vge+, 1 vge+, 1 vg+e, 1vg+e

3) The F2 phenotypic ration is

9 wild type :3 vestigial :3 ebony:1 vestigial ebony

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