1. In Drosophila melanogaster (fruit fly) experiment, if we are going to cross male and female red-eyed fruit flies, we have the resulting offspring ratio of 50% red-eyed for female, 25 % for red-eyed male and 25% for white-eyed male. Females which are either homozygous or heterozygous for a trait still expressed eye redness whereas males can easily be affected. Why is this so? a. Females are the carriers of a gene for eye redness b. Y chromosome is responsible for red eyes in fruit flies, c. The gene for eye redness is an X-link dominant trait, d. Having a red-eyed trait is dominantly expressed by females

1. In Drosophila melanogaster (fruit fly) experiment, if we are going to cross male and female red-eyed fruit flies, we have the resulting offspring ratio of 50% red-eyed for female, 25 % for red-eyed male and 25% for white-eyed male. Females which are either homozygous or heterozygous for a trait still expressed eye redness whereas males can easily be affected. Why is this so? a. Females are the carriers of a gene for eye redness b. Y chromosome is responsible for red eyes in fruit flies, c. The gene for eye redness is an X-link dominant trait, d. Having a red-eyed trait is dominantly expressed by females

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...

See similar textbooks

Similar questions

1.In Drosophila melanogaster body color is controlled by one gene while wing shape is controlled by a second gene. Gray body color is dominant to black body color, and normal wings are dominant to vestigial wings. Flies homozygous for gray body color and vestigial wings are crossed with flies homozygous for black body color and normal wings. A.compare the possible f2 generation genotypes and phenotypes and proportions if these two traits. B.How does your answer change if one of the original parents is homozygous for gray body color and normal wings while the other has black body color and vestigial wings?
0. In Drosophila, the gene for cinnabar eye color is onchromosome 2, and the gene for scarlet eye color is onchromosome 3. A fly homozygous for both recessivecinnabar and scarlet alleles (cn/cn; st/st) is white-eyed.a. If male flies (containing chromosomes with thenormal gene order) heterozygous for cn and st allelesare crossed to white-eyed females homozygous forthe cn and st alleles, what are the expected phenotypes and their frequencies in the progeny?b. One unusual male heterozygous for cn and st alleles,when crossed to a white-eyed female, produced onlywild-type and white-eyed progeny. Explain the likelychromosomal constitution of this male.c. When the wild-type F1 females from the cross withthe unusual male were backcrossed to normal cn/cn;st/st males, the following results were obtained:wild type 45%cinnabar 5%scarlet 5%white 45%Diagram a genetic event at metaphase I that couldproduce the rare cinnabar or scarlet flies among theprogeny of the wild-type F1 females.
1. Mendel obtained his initial pea plant varieties from local breeders who were developing new varieties that might be useful or interesting. To generate these new varieties, breeders formed hybrids between existing varieties of different phenotypic characteristics by cross pollination, using techniques they doubtless taught to Mendel. After producing a hybrid, they allowed several generations of self-pollination, as happens naturally if the flowers are not disturbed. a. How many generations would it take for a breeder to have produced new pure-breeding varieties using this approach? iv. What is the probability that an individual in each of these generations (F2, F3, and F10) would be homozygous for one or the other allele of this gene? [Broad hint: if they’re not heterozygous, they’re homozygous!]
Kernel color in wheat Red kernel color in wheat results from the interaction between two dominant alleles. With only one dominant allele, the phenotype is brown while in the absence of any dominant allele, the phenotype is white. Suppose that plants of a variety that is true breeding for red kernels are crossed with plants true breeding for white kernels. What specific type of interaction can be observed? A. duplicate dominant genes B. duplicate genes with cumulative effects C. complementary genes D. dominant epistasis (case 2)
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…
3. Two Drosophila flies that had normal (transparent, long) wings were mated. In the progeny, two new phenotypes appeared, dusky wings (having a semi-opaque appearance) and clipped wings (with squared ends). The progeny were as follows: Females: Males: 179 transparent, long 58 transparent, clipped 92 transparent, long 89 dusky, long 28 transparent, clipped 31 dusky, clipped a) Provide a genetic explanation for these results, showing genotypes of parents and of all progeny classes under your model. b) Design a test for your model.
1.) Using the table above as a guide, determine the map distance between the linked genes for eye colour and wing type in the following experiment. You perform the following cross: PpVv × ppvv. You count 1000 offspring in the F1 generation. You find that 406 of the flies have normal eyes and normal wings, 398 have purple eyes and vestigial wings, 96 have normal eyes and vestigial wings, and 100 have purple eyes and normal wings. 2. From previous research findings, you know that the distance between the gene for eye colour and the gene for body colour is 12.2 map units, and the gene for body colour is 7.4 map units away from the gene for wing type. All three genes are on the same chromosome. Draw a chromosome map showing the relative distances between the three linked genes. 3.) You conduct the same cross again, but this time you get an almost exact 1:1 ratio of flies with normal eyes and normal wings to flies with purple eyes and vestigial wings. There are no recombinant types.…
. 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…
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)
D In fava bean plant the seed color can be coded by two alleles, green (G) which is dominant and purple (g) which is recessive. A gardening hobbyist performed a cross between 2 true-breeding lines P1 and P2 that respectively have green and purple seeds. Answer the following questions in regard to the hobbyist experiment. 1) What are the genotypes of the parental lines A and B? what are the genotypes of the gametes of each parent? 2)What is the phenotype and genotype of the F1 generation of the cross? 3) What are the proportions of the genotypes of the F2 generation? 4)What are the proportions of the phenotypes of the F2 generation?
5.TRIHYBRID CROSS Determine all possible gametes of a cross between the gerbils and their fur color genes where hair shaft color is agouti (B) vs. black (b) which is physically caused by different deposition of melanin in the hair shaft; coat color pattern is solid (P) vs. piebald (p) and the modifier which is wild type (M) vs. modified (m) (affects melanin deposition). A trihybrid cross for all three traits would be BbPpMm x BBPPM. Practice this in Punnett square.
In Drosophila melanogaster white (w) and miniature (m) wings are controlled by X-linked recessive genes with a recombination fruequency between them of approximately 38%. Show the sexes, phenotypes and proportions of offspring expected from the following mating:a. ++/wm female X wm maleb. +m/w+ female X w+ malec. w+/+m female X ++ maleIf we assume that white eyes and miniature wings are not x-linked but are linkedto the autosomal genes, what phenotypic frequencies would you expect from this cross: ++/wm female X ++/wm male?