4. In Drosophila melanogaster the wild-type eye colour 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. Fi 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.

4. In Drosophila melanogaster the wild-type eye colour 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. Fi 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.

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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2. In Drosophila sp. Red eyes are dominant over white eyes. Normal wings are dominant over vestigial wings. Homozygous red eyes normal wings females were crossed with homozygous white eyes and vestigial wings males. The F2 generation after a test cross are as below Phenotype Red eyes, normal wings White eyes, vestigial wings Red eyes, vestigial wings White eyes, normal wings Amount 1670 1590 425 435 a) Are the wings and eyes colour genes linked? b) Show all the crosses c) Calculate the recombination frequency value. d) What is the distance between the wings and eyes colour genes?
. The normal eye color of Drosophila is red, but strains inwhich all flies have brown eyes are available. Similarly,wings are normally long, but there are strains with shortwings. A female from a pure line with brown eyes andshort wings is crossed with a male from a normal pureline. The F1 consists of normal females and short-wingedmales. An F2 is then produced by intercrossing the F1.Both sexes of F2 flies show phenotypes as follows:38 red eyes, long wings38 red eyes, short wings18 brown eyes, long wings18 brown eyes, short wingsDeduce the inheritance of these phenotypes; useclearly defined genetic symbols of your own invention.State the genotypes of all three generations and thegenotypic proportions of the F1 and F2.Unpacking Problem 31Before attempting a solution to this problem, try answering thefollowing questions:1. What does the word normal mean in this problem?2. The words line and strain are used in this problem.What do they mean, and are they interchangeable?3. Draw a simple…
5. A cross between two wild-type flies gave progeny all of which were wild type. When vg e they were test crossed to flies the following results were obtained: vg e (a) 4 of the test crosses gave wild type, vestigal ebony, vestigal and ebony in a 1:1:1:1 ratio. (b) 4 of the test crosses gave all wild type. (c) 4 of the test crosses gave vestigal and wild type in a 1:1 ratio. (d) 4 of the test crosses gave ebony and wild type in a 1:1 ratio. What are the genotypes of the original pair of wild-type flies?
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.
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…
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?
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)
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…
8. An insect from a strain breeding true for white eyes (RRww) was crossed to an insect from a strain breeding true for cream eye (rrWW). The F1s all had red eyes. o The Fls were intercrossed to produce an F2 generation that consisted of 175 red- eyed:62 cream:81 white eyed. A sqyT * O qyT ( 0 sqy x 0 sqyT (b i. Provide the genetics of inheritance of this trait. ii. Provide the genotypes for the F1s and F2s of this cross. boold B sqyt dirwydad a ot drid svag sqyt boold a sy diw mow A 8 oyd zodio ad bas boold A sayt zad ono dist ori ed of misls nom tertib 9. In wild sunflowers, populations occur that are either yellow flowers (wild type) or white flowers. One variety of true breeding white flowered plants was crossed to another pure strain of white flowered plant. The resulting F1 progeny were yellow flowered plants. When the F1 progeny were intercrossed, the offspring were 56 yellow flowered and 44 white flowered. From the results of these crosses, how many genes control the flower…
2. Three different pure-breeding strains of corn that produce ears with white kernels were crossed to eachother. In each case, the F1 plants were all red, whileboth red and white kernels were observed in the F2generation in a 9:7 ratio. These results are summarized in the following table.F1 F2white-1 × white-2 red 9 red : 7 whitewhite-1 × white-3 red 9 red : 7 whitewhite-2 × white-3 red 9 red : 7 whitea. How many genes are involved in determiningkernel color in these three strains?b. Define your symbols and show the genotypes for thepure-breeding strains white-1, white-2, and white-3.c. Diagram the cross between white-1 and white-2,showing the genotypes and phenotypes of the F1and F2 progeny. Explain the observed 9:7 ratio.
3. The allele b gives Drosophila flies a black body and b+ gives brown, the wild-type phenotype. The allele wx of a separate gene gives waxy wings and wx+ gives nonwaxy, the wild-type phenotype. The allele cn of a third gene gives cinnabar eyes and cn+ gives red, the wild-type phenotype. A female heterozygous for these three genes is testcrossed, and 1000 progeny are classified as follows: 5 wild type; 6 black, waxy, cinnabar; 69 waxy, cinnabar; 67 black; 382 cinnabar; 379 black, waxy; 48 waxy; and 44 black, cinnabar. Are these three genes linked? If so, draw a map of the chromosomes in the heterozygous parent, showing the order, arrangement, and map distance between the linked genes.
14. A wildtype fruit fly (heterozygous for gray body and normal wings) is mated 2 poin with a black fly with vestigial wings. Offspring: 778-wild type 785-black vestigial 158-black-normal wings 162 gray body-vestigial wings. 1. What is the recombination frequency between these genes? 2. Are the genes linked? Explain why or why not. *