4. In a genetic experiment with fruit-fly Drosophila melanogaster, F1 females resulting from a cross between two pure-breeding parental (P) fly strains were mated with wild- type males. All of the 1000 female progeny of this mating examined were phenotypically wild-type, whereas the 1000 male progeny examined exhibited different phenotypes in different numbers shown below (any trait not specified is wild-type): Phenotype wild-type bobbed-hair fused-vein sable-body bobbed-hair & fused-vein Number of F2 male progeny 6 75 396 26 29 384 bobbed-hair & sable-body fused-vein & sable-body 80 bobbed-hair, fused-vein & sable-body 4 (a) What are the respective modes of inheritance of bobbed-hair, fused-vein and sable- body traits? From which observation(s) do you draw these conclusions? (b) State the phenotypes of the following classes of individuals: i. F1 females, ii. Two parental (P) strains, separately. (c) Find the relative genetic locations of the genes controlling these traits, and possible crossover interference between them if they are linked.

4. In a genetic experiment with fruit-fly Drosophila melanogaster, F1 females resulting from a cross between two pure-breeding parental (P) fly strains were mated with wild- type males. All of the 1000 female progeny of this mating examined were phenotypically wild-type, whereas the 1000 male progeny examined exhibited different phenotypes in different numbers shown below (any trait not specified is wild-type): Phenotype wild-type bobbed-hair fused-vein sable-body bobbed-hair & fused-vein Number of F2 male progeny 6 75 396 26 29 384 bobbed-hair & sable-body fused-vein & sable-body 80 bobbed-hair, fused-vein & sable-body 4 (a) What are the respective modes of inheritance of bobbed-hair, fused-vein and sable- body traits? From which observation(s) do you draw these conclusions? (b) State the phenotypes of the following classes of individuals: i. F1 females, ii. Two parental (P) strains, separately. (c) Find the relative genetic locations of the genes controlling these traits, and possible crossover interference between them if they are linked.

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter13: Genes, Chromosomes, And Human Genetics

Section: Chapter Questions

Problem 8TYK: Another gene in Drosophila determines wing length. The dominant wild-type allele of this gene...

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In cats, the genotype AA produces tabby fur color; Aa is also a tabby, and aa is black. Another gene at a different locus is epistatic to the gene for fur color. When present in its dominant W form (WW or Ww), this gene blocks the formation of fur color and all the offspring are white; ww individuals develop normal fur color. What fur colors, and in what proportions, would you expect from the cross AaWw Aa Ww?
In sweet pea plants, an allele for purple flowers. (P) is dominanl when paired with a recessive allele for red flowers (p). An allele for Jang pollen grains (L) is dominant when paired with a recessive allele for round pollen grains (L). Bateson and Punnett crossed a plant having purple flowers and long pollen grains with one having white flowers and round pollen grains. All F1 offspring have purple flowers and long pollen grains. Among the F2 generation, the researchers observed the following phenotypes: 296 purple flowers/long pollen grains 19 purple /lower/ round pollen grains 27 red flowers/long pollen grains 85 red flowers/round pollen grains What is the best explanation for these results?
6. In Drosophila melanogaster, the wild-type eye colour is dark red. A pure-breeding mutant strain with white eyes also exists. When reciprocal crosses are made between (i) a white-eyed male a wild-type female, and (ii) a white-eyed female a wild-type male, the progeny are as follows: (1) P: White-eyed male x red-eyed female F1: red-eyed males and females F2: 100 progeny; 27 red-eved males, 24 white-eyed males, 49 red-eyed females (ii) P: red eyed male x white-eyed female F1: white-eyed males and red-eyed females F2: 100 progeny; 23 red-eved males 26 white-eyed males, 28 red-eyed females, 23 white-eyed females. How do you interpret these data?
2. a. A Drosophila male from a true-breeding stockwith scabrous eyes was mated with a female from atrue-breeding stock with javelin bristles. Both scabrous eyes and javelin bristles are autosomal recessive mutant traits. The F1 progeny all had normaleyes and bristles. F1 females from this cross weremated with males with both scabrous eyes andjavelin bristles. Write all the possible phenotypicclasses of the progeny that could be produced from the cross of the F1 females with the scabrous, javelin males, and indicate for each class whether it is arecombinant or parental type.b. The cross in part (a) yielded the following progeny:77 scabrous eyes and normal bristles; 76 wild type(normal eyes and bristles); 74 normal eyes andjavelin bristles; and 73 scabrous eyes and javelinbristles. Are the genes governing these traits likelyto be linked, or do they instead assort independently? Why?c. Suppose you mated the F1 females from the crossin part (a) to wild-type males. Why would thiscross fail…
1. The allele G for yellow stigma is completely dominant to green (g). Supposingtwo strains of autotetraploid plants are available and their genotypes are as follows:GGgg – in this plant the gene is close to the centromereGggg – in this plant the gene is far from the centromere If these two plants are crossed:a) provide the gametes that can be obtained from the two plants;b) provide the genotypic and phenotypic ratios of the offspring. 2. Consider the illustration below. Diagram the configuration you would observe at Anaphase I if crossing-over happens within the inversion. (IMAGE ATTACHED)
I. Male Drosophila from a true-breeding wild-typestock were irradiated with X-rays and then mated withfemales from a true-breeding stock carrying the following recessive mutations on the X chromosome:yellow body (y), crossveinless wings (cv), cut wings(ct), singed bristles (sn), and miniature wings (m).These markers are known to map in the order:y - cv - ct - sn - mMost of the female progeny of this cross were phenotypically wild type, but one female exhibited ct and snphenotypes. When this exceptional ct sn female wasmated with a male from the true-breeding wild-typestock, twice as many females as males appearedamong the progeny.a. What is the nature of the X-ray-induced mutationpresent in the exceptional female?b. Draw the X chromosomes present in the exceptional ct sn female as they would appear duringpairing in meiosis.c. What phenotypic classes would you expect to seeamong the progeny produced by mating the exceptional ct sn female with a normal male from a truebreeding wild-type…
4. In Drosophila melanogaster, a yellow-bodied (dark coloured) male with vestigial (underformed) wings is crossed to a wildtype female (brown body, red eyes). The F1 generation are all wildtypes. An F1 male and female are crossed and the F2 progeny consists of 16 vestigial-winged males with yellow bodies, 48 yellow males with normal wings, 15 males with vestigial wings and yellow bodies, 49 wildtype males, 31 vestigial winged females with brown bodies and 97 wildtype females. Explain the inheritance pattern of the 2 genes.
6). To investigate the genetic control of locomotive behavior in the diploid nematode, Caenorhabditis elegans, eight "wiggly" mutants were isolated, which wiggle in an uncoordinated way rather than smoothly gliding. These eight mutants were crossed together in all possible pairwise combinations, yielding the results summarized in the table above (+ means that all the progeny were wild type, and m means that all the progeny showed the wiggly mutant phenotype). Organize the eight mutations into con lementation groups, each consisting of a group of mutations affecting the same gene. 1 2 3 4 5 6 7 8 1 E N+E 2 3+1 m + m 4 5 + m m E+ + + EE 6 ++E E+ +EE m m + + + + + + + + + m 7 8 ++4 ∞+E +E m m ++ E
2. Drosophila females heterozygous for three recessive x-linked markers y (yellow bodies), ct (cut wings), and m (miniature wings) were crossed to y ct m males and the following progeny were obtained. F1 Phenotype Yellow, cut, miniature Wildtype Yellow Cut, miniature miniature Number cut 60 63 20 13 Yellow, cut 15 Yellow, miniature 5 22 2 a) F1 Genotype b) Recombinant or Parental? c) SCO, DCO, or NONE? a) Fill in the table with the genotypes of each progeny type, use + to indicate wildtype/dominant traits, show separate homologues. b) In the table, identify whether each progeny type is Recombinant (R) or Parental (P). c) In the table, identify whether each progeny type results from a single crossover (SCO), a double crossover (DCO), or no crossing over (NONE). d) Diagram the parental cross, clearly indicating allelic contributions from each homologue of parental flies. Heterozygous wild-type Female Fly X Hemizygous mutant Male fly // // e) Draw the genetic map showing correct order and…
2. In the fruit fly, Drosophila melanogaster, a spineless (no wing bristles) female fly ismated to a male that is claret (dark eyes) and hairless (no thoracic bristles).Phenotypically wild-type F1 female progeny were mated to fully homozygous (mutant)males, and the following progeny (1000 total) were observed:Phenotypes Number Observedspineless 321wild 38claret, spineless 130claret 18claret, hairless 309hairless, claret, spineless 32hairless 140hairless, spineless 12(a) Which gene is in the middle?(b) With respect to the three genes mentioned above, what are the genotypes of thehomozygous parents used in making the phenotypically wild F1 heterozygote?(c) What are the map distances between the three genes?(d) What is the coefficient of coincidence?
12) You are studying two flies that you found in your lab one has bristly hair the other has dumpy wings. You cross these two mutants together and all the resultant flies are wild type. You then cross these animals to a double mutant and collect the following offspring. Phenotype Observed Normal 92 Bristly Hair 122 Dumpy Wings 129 Bristly Hair and Dumpy Wings 97 Which are your dominant alleles? Check all that apply O Bristly Hair O Normal Wings O Dumpy Wings O Normal hair 13) Assuming that these traits are sorting in a Mendelian way, and given that you collected 440 flies from your cross, how many flies do you expect that have just bristly hair _(1). ;bristly hair and dumpy wings_(2). 1) 2) 14) Given the numbers you just calculated for expected and the observed listed earlier, what is the chi-squared value for this cross? Numerical answer
4. In Drosophila melanogaster the wild-type eye çolour is dark red. A pure-breeding mutant strain with brown eyes also exists. When brown-eyed flies are crossed to wild-type flies all of the Fi progeny are dark red-eyed. F1 flies were intercrossed and the F2 analvsed. In a total of 200 F2 flies there were 141 wild- type flies and 59 brown-eyed flies. There was no difference in the result between male and female F2 progeny. Some F1 flies were test crossed to brown-eyed flies and of 88 progeny, 48 were wild- type and 40 were brown-eyed with no differences between the sexes. - Interpret these results as fully as possible. b) A cross between two wild-type flies gave progeny all of which were wild type. When they were test crossed to flies the following results were obtained: vg e i) % of the test crosses gave wild type, westigal ebony, vestigal and ebony in a 1:1:1:1 ratio. ii) 4 of the test crosses gave all wild type. iii) % of the test crosses gave yestigal and wild type in a 1:1 ratio.…