Recessive maternal effect genes are identified in flies (for example)when a phenotypically normal mother cannot produce any normaloffspring. Because all of the offspring are dead, this female fly cannot be used to produce a strain of heterozygous flies that could beused in future studies. How would you identify heterozygous individuals that are carrying a recessive maternal effect allele? Howwould you maintain this strain of flies in a laboratory over manygenerations?

Recessive maternal effect genes are identified in flies (for example)when a phenotypically normal mother cannot produce any normaloffspring. Because all of the offspring are dead, this female fly cannot be used to produce a strain of heterozygous flies that could beused in future studies. How would you identify heterozygous individuals that are carrying a recessive maternal effect allele? Howwould you maintain this strain of flies in a laboratory over manygenerations?

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter11: Genome Alterations: Mutation And Epigenetics

Section: Chapter Questions

Problem 16QP: Familial retinoblastoma, a rare autosomal dominant defect, arose in a large family that had no prior...

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You ave established a mutant line of flies with a balancer chromosome. The balancer chromosome includes GFP and a mutation in gene X that causes flies to be sterile in the homozygous state. The recessive mutation that you are studying is in gene Y, and causes flies to develop two tail ends in the homozygous state. This mutation is lethal in the homozygous state. For each of the following phenotypes in the balanced mutant line, what alleles are present and in how many copies? a.) Glows green, fertile (Select] b.) Glows green, sterile [Select) c.) does not glow green, two tails (Select] If you crossed a fly from your balanced line with the following flies, what proportion of the offspring would glow green and be fertile? d.) wild-type [Select ) e.) fly with balancer chromosome from parental generation [ Select ]
. In 1919, Calvin Bridges began studying an X-linkedrecessive mutation causing eosin-colored eyes inDrosophila. Within an otherwise true-breedingculture of eosin-eyed flies, he noticed rare variantsthat had much lighter cream-colored eyes. By intercrossing these variants, he was able to make a truebreeding cream-eyed stock. Bridges now crossedmales from this cream-eyed stock with true-breedingwild-type females. All the F1 progeny had red (wildtype) eyes. When F1 flies were intercrossed, the F2progeny were 104 females with red eyes, 52 maleswith red eyes, 44 males with eosin eyes, and14 males with cream eyes. Assume that thesenumbers represent an 8:4:3:1 ratio.a. Formulate a hypothesis to explain the F1 and F2results, assigning phenotypes to all possiblegenotypes.b. What do you predict in the F1 and F2 generations if the parental cross is between truebreeding eosin-eyed males and true-breedingcream-eyed females?c. What do you predict in the F1 and F2 generationsif the parental cross is…
In the experiment of Figure shown, Stern followed the inheritancepattern in which females carried two abnormal X chromosomesto correlate genetic recombination with the physical exchange ofchromosome pieces. Is it necessary to use a strain carrying twoabnormal chromosomes, or could he have used a strain in whichfemales carried one normal X chromosome and one abnormal Xchromosome with a deletion at one end and an extra piece of the Ychromosome at the other end?
Let’s suppose that you have made a karyotype of a female fruit flywith red eyes and found that it has three X chromosomes insteadof the normal two. Although you do not know its parents, you doknow that this fly came from a mixed culture of flies in whichsome had red eyes, some had white eyes, and some had eosin eyes.Eosin is an allele of the same gene that has white and red alleles.Eosin is a pale orange color. The red allele is dominant and thewhite allele is recessive. The expression of the eosin allele, however, depends on the number of copies of the allele. When femaleshave two copies of this allele, they have eosin eyes. When femalesare heterozygous for the eosin allele and the white allele, they havelight-eosin eyes. When females are heterozygous for the red alleleand the eosin allele, they have red eyes. Males that have a singlecopy of the eosin allele have eosin eyes.You cross the XXX red-eyed female with a white-eyed male andcount the numbers of offspring. You may assume that…
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The Drosophila chromosome 4 is extremely small;virtually no recombination occurs between genes onthis chromosome. You have available three differentlymarked chromosome 4s: one has a recessive allele ofthe gene eyeless (ey), causing very small eyes; one hasa recessive allele of the cubitus interruptus (ci) gene,which causes disruptions in the veins on the wings;and the third carries recessive alleles of both genes.Drosophila adults can survive with two or three, butnot with one or four, copies of chromosome 4.a. How could you use these three chromosomes tofind Drosophila mutants with defective meiosescausing an elevated rate of nondisjunction?b. Would your technique allow you to discriminatenondisjunction occurring during the first meioticdivision from nondisjunction occurring during thesecond meiotic division?c. What progeny types would you expect if a flyrecognizably formed from a gamete produced bynondisjunction were testcrossed to a fly homozygous for a chromosome 4 carrying both ey…
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