Can you please help? 1. In Drosophila melanogaster, curled wings (cu) was one of the first mutants described byThomas Hunt Morgan more than 100 years ago (in 1915). The gene for curled wings is on thesame chromosome as the gene for the mutant sepia eyes (se). They are 24 map units apart onchromosome 3. Both traits are encoded by two mutant alleles that are recessive to those thatproduce wild-type traits (cu+ and se+). A fly that is homozygous for sepia eyes and curled wingsis crossed with a fly homozygous for the wild- type traits. The F1 generation all have the wildtype phenotype. In a testcross, the F1 progeny are mated with flies that have sepia eyes andcurled wings.1a. Create a drawing to show the chromosomes, allele arrangements and phenotypes of the F 1parents in the testcross and the nonrecombinant and recombinant F 2 progeny produced fromthe testcross.1b. If 360 offspring are produced in F1 testcross, what is the number of progeny expected foreach F2 phenotypic class?1c. Is the F1 heterozygote in coupling or repulsion?

Genetics is a part of biology that deals with the transmission of characteristics from one…

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In Drosophila melanogaster, curled wings (cu) was one of the first mutants described by

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 7TYK: In Drosophila, two genes, one for body color and one for eye color, are carried on the same...

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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.
Drosophila researchers have collected many strainsthat carry a single recombinant P element containing awild-type white gene (a P[w+] transgene) inserted intoa known genomic location. These strains can be used tomap the location of any mutant gene in the fly genome.Investigators performed a testcross to map arecessive mutation rough (ro), which causes rougheyes, relative to a P[w+] element on chromosome 3.Females heterozygous for the P[w+] on one chromosome 3 and a ro− mutation on the other, homologouschromosome 3 were crossed to ro−/ro− males, and theprogeny in the following list were obtained. In boththe parents and the progeny, the endogenous whitegene is nonfunctional—the flies have red eyes onlyif they contain the P[w+] transgene.145 red, smooth (wild-type) eyes152 white, rough eyes2 white, smooth eyes1 red, rough eyesa. Are ro and the P[w+] linked? If so, how many mapunits separate them?b. The data in part (a) do not indicate on which sideof the P[w+] (toward the centromere or…
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
In Drosophila, a heterozygous female for the X-linkedrecessive traits a, b, and c was crossed to a male that phenotypically expressed a, b, and c. The offspring occurred inthe following phenotypic ratios.+ b c 460a + + 450a b c 32+ + + 38a + c 11+ b + 9 No other phenotypes were observed.(a) Determine the correct sequence and construct amap of these genes on the X chromosome ?
Drosophila P elements were discovered because ofa phenomenon called hybrid dysgenesis—sterilityof particular hybrid progeny. When scientists in the1970s crossed their D. melanogaster laboratorystrains to flies of the same species obtained fromnatural environments outside the lab, they observeda remarkable result: The progeny of the crosseswere sterile, but only when outside males werecrossed with lab strain females. Progeny resultingfrom crosses of outside females with lab maleswere perfectly normal.DNA analysis revealed that while the genomesof the outside flies contain P elements, the lab flygenomes have none. Apparently, P elements spreadthroughout the wild population of D. melanogasterafter the capture of the originators of present-daylaboratory strains over 100 years ago.a. The hybrid progeny are sterile because their germline cells have a high rate of mutation and chromosomal rearrangement (dysgenesis) caused by highrates of P element mobilization. Explain howP element movement…
In Drosophila, a heterozygous female for the X-linkedrecessive traits a, b, and c was crossed to a male that phenotypically expressed a, b, and c. The offspring occurred inthe following phenotypic ratios.+ b c 460a + + 450a b c 32+ + + 38a + c 11+ b + 9 No other phenotypes were observed.(a) What progeny phenotypes are missing? Why?
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1. The easily observed external structures in insects, such as different pairs of legs, antennae, and wings form from imaginal discs. a) How is the identity of the different Drosophila imaginal discs established in the embryo—for example, how is it determined whether a disc will form a wing, a leg, or some other structure? b) Dominant mutants in the gene Antennapedia result in fore legs forming in the location where antennae are expected. How does this mutant phenotype illustrate your response to Part a?
1. A newly discovered species of dung beetle has 2n = 16 chromosomes. It mates with a closely related beetle species that has 2n = 12 chromosomes. How many chromosomes would there be in an allotriploid beetle produced from this cross? *goes with image 1* 1. The Cavendish banana (genome = AAA), the variety most often sold in grocery stores, has what type of genome? (indicate the ploidy and if its an auto- or allo-) 2. Some bananas have genome AAB, which is an example of which kind of polyploidy? (indicate the ploidy and if its an auto- or allo-) *goes with image 2* 1. Which species of bacteria is not a heterotroph? (choose all that apply) 2. Which two species contain more cytoplasmic phospholipid membranes than the others? (choose 2) 3. Which species is capable of directed movement?(choose 1) 4. Which species have a cell wall that consists partly of an outer membrane of lipopolysaccharide? (choose all that apply) 5. Species 4 is pathogenic if it gains access to the human…
4. a. Give at least three examples of types of mutationsthat would disrupt the process of mitotic chromosomesegregation. That is, explain in what DNA structuresor in genes encoding what kinds of proteins youwould find these segregation-disrupting mutations.b. How could you use yeast artificial chromosomes(YACs) to find such mutations in S. cerevisiae?
6. A person is simultaneously heterozygous for two autosomal genetic traits. One is a recessive condition foralbinism (alleles A and a); this albinism gene is foundnear the centromere on the long arm of an acrocentricautosome. The other trait is the dominantly inheritedHuntington disease (alleles HD and HD+). TheHuntington gene is located near the telomere of oneof the arms of a metacentric autosome. Draw all copies of the two relevant chromosomes in this person asthey would appear during metaphase of (a) mitosis,(b) meiosis I, and (c) meiosis II. In each figure, labelthe location on every chromatid of the alleles forthese two genes, assuming that no recombinationtakes place.
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…