To analyze:
The bicoid is characterized as a coordinate, maternal effect gene. Based on this, answer the following:
Determine the
Determine the phenotype of progeny produced from a cross between a female that is homozygous for a loss of function bicoid allele and a wild type male.
Provide an explanation on, if losses of bicoid function in the egg results in lethality during embryogenesis how are females homozygous for bicoid produced. Also determine phenotype of a male homozygous for bicoid loss of function alleles.
Introduction:
Bicoid is an example of a maternal effect gene. The phenotype result from maternal effect gene is identified by the mother genotype and not by the organism phenotype. This is because the egg receives protein and mRNA needed for proper development from the mother for the determination and development of a body axis in an organism. Bicoid is essential, thus, it is also termed as axis determination gene.
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Genetic Analysis: An Integrated Approach (3rd Edition)
- In Drosophila, an X-linked recessive mutation, (s) causes irregular wing margins. Give the genotypes, phenotypes and phenotypic ratio of the F1 and F2 offspring in the following crosses a. scalloped female crossed with a normal male b. scalloped male crossed with a homozygous normal female. Compare these results to those that would be obtained if the scalloped gene is autosomal.arrow_forwardDrosophila, yellow body color is due to an X-linked gene that is recessive to the gene for gray body color.a. A homozygous gray female is crossed with a yellow male. The F1 are intercrossed to produce the F2. Give the genotypes and phenotypes, along with the expected proportions, of the F1 and F2 progeny.b. A yellow female is crossed with a gray male. The F1 are intercrossed to produce the F2. Give the genotypes and phenotypes, along with the expected proportions, of the F1 and F2 progeny.c. A yellow female is crossed with a gray male. The F1 females are backcrossed with gray males. Give the genotypes and phenotypes, along with the expected proportions, of the F2 progeny.d. If the F2 flies in part b mate randomly, what are the expected phenotypes and proportions of flies in the F3?arrow_forwardIn drosophila, a recessive mutation (m-) of a maternal effect gene results in an abnormal phenotype wherein homozygous (m-m-) females produce eggs that cannot support embryonic development. Homozygous (m-m-) males, however, can still produce viable sperm. (A) Using m+ to denote a normal gene, determine the genotypes and phenotypes of the F1s produce by a cross between a heterozygous female and a recessive male. (B) From the offspring, backcross the recessive female with the paternal strain. What are the genotypes and phenotypes of the F2s? (C) If m-m- females produce useless eggs, then how are m-m- produced?arrow_forward
- Please explain how you do this question step by step I am very confused! thank you:) You have three independent mutant alleles in the Drosophila gene no-antenna: nan1, nan2 and nan3. You determine the phenotype of Drosophila that are heterozygous for the three alleles (heterozygous for a wild-type allele and a mutant allele), and that are homozygous for the three mutant alleles. The antenna is composed of three segments that are followed at the distal end by a feathery arista (that is the antenna is composed of three segments and an arista). Allele nan1 nan2 nan3 heterozygous Wild-type No arista Wild-type homozygous No arista No antenna No antenna nan1 is a __x__ allele, nan2 is a __y__ allele, and nan3 is a __z__ allele. X Y Z A Dominant negative Null Hypomorphic B Null Dominant negative Hypomorphic C Null Hypomorphic Dominant negative D Hypomorphic Dominant negative Null E Dominant negative Hypomorphic Null Referencing the table above, select the…arrow_forwardDrosophila females heterozygous for three recessive mutations, a, b, and c , were crossed to males homozygous for all three mutations.The cross yielded the following results: in the image Q. Construct a linkage map showing the correct order of these genes and estimate the distances between them.arrow_forwardIn drosophila, a recessive mutation (m-) of a maternal effect gene results in an abnormalphenotype wherein homozygous (m-m-) females produce eggs that cannot support embryonicdevelopment. Homozygous (m-m-) males, however, can still produce viable sperm. Using m+ todenote a normal gene, determine the genotypes and phenotypes of the F1s produce by a crossbetween a heterozygous female and a recessive male. From the offspring, backcross the recessivefemale with the paternal strain. What are the genotypes and phenotypes of the F2s?arrow_forward
- Deranged: is a phenotype in Drosophila in which the thoracic bristles are disarranged and the wings held vertically upward. Crosses between deranged females and normal males, each from pure stock cultures, result in a 1:1 ratio of normal females to deranged males among the progeny. What does this show? A. The gene for deranged is autosomal and dominant. B. The gene for deranged is autosomal and recessive. C. The gene for deranged is X-linked and dominant. D. The gene for deranged is X-linked and recessive. E. Deranged is determined by two genes interacting epistatically.arrow_forwardIn Drosophila, the wildtype eye color is black. In the laboratory, you screened for mutants than when homozygous results to different eye phenotypes. You found two mutants 1) red eye (re) and 2) white eye (we). You performed a complementation test and the resulting eye phenotype was gray. From the results, what conclusion can you make? A. There was complementation, thus the two mutations are alleles of different genes. B. There was no complementation, thus the two mutations are alleles of different genes. C. The two mutations failed to complement, thus they are alleles of different genes. D. The two mutations failed to complement, thus they are alleles of the same genes. E. The two mutations complemented, hence they are likely controlled by different genes.arrow_forwardThe Drosophila gene Sex lethal (Sxl) is deserving of itsname. Certain alleles have no effect on XY animals butcause XX animals to die early in development. Other alleles have no effect on XX animals but cause XY animals to die early in development. Thus, some Sxl allelesare lethal to females, while others are lethal to males.a. Would you expect a null mutation in Sxl to causelethality in males or in females? b. Why do Sxl alleles of either type cause lethality ina specific sex?The gene transformer (tra) gets its name from sexualtransformation, as some tra alleles can change XXanimals into morphological males, while other traalleles can change XY animals into morphologicalfemales.c. Which of these sex transformations would becaused by null alleles of tra and which would becaused by constitutively active alleles of tra?d. In contrast with Sxl, null tra mutations do notcause lethality either in XX or in XY animals.However, the Sxl protein regulates the productionof the Tra protein. Why…arrow_forward
- 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…arrow_forwardIn Drosophila, the X-linked recessive mutation vermilion (v) causes bright red eyes, in contrast to the brick-red eyes of wild type. A separate autosomal recessive mutation, suppressor of vermilion (su-v), causes flies homozygous or hemizygous for v to have wildtype eyes. In the absence of vermilion alleles, su-v has no effect on eye color. Determine the F1 and F2 phenotypic ratios from a cross between a female with wild-type alleles at the vermilion locus, but who is homozygous for su-v, with a vermilion male who has wildtype alleles at the su-v locusarrow_forwardEC1. In drosophila the cw (curly wings) gene and eb (ebony body) genes are found on the same chromosome 20 map units apart. A cross was made between an ebony bodied parental strain and a curly winged parental strain and the F1’s were test crossed. a) What are the genotypes of the parental strains? b) What are the genotypes of the F1’s? c) What is the genotype of the tester strain? d) What progeny phenotypes and genotypes do you expect, and in what proportions? For phenotypes use the mutant phenotype for any that the flies have, and wild-type if they have none. EC2. Here is a tetrad produced by mating a H Y strain to an h y strain. a) What is the tetrad type? b) What has recombined with what? EC3. In corn, a dihybrid for the recessive genes a and b is test-crossed. The distribution of the phenotypes is as follows: A B 122A b 118a B 81a b 79 a) Do the genes appear to be sorting independently? Look at map units here. b) Test your hypothesis with a chi-squared test.arrow_forward
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