The Hoxd
a. What would be the consequence of ectopically expressing Hoxd
b. You wish to examine the effect of loss
Figure 18.18
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Genetic Analysis: An Integrated Approach (3rd Edition)
- A maternal effect gene in Drosophila, called torso, is found as a recessive allele that prevents the correct development of anterior- and posterior-most structures. A wild-type (homozygous) male is crossed to a female of unknown genotype. This mating produces 100% larva that are missing their anterior- and posterior-most structures and therefore die during early development. What is the genotype and phenotype of the female fly in this cross? What are the genotypes and phenotypes of the female fly’s parents? Show COMPLETE cross.arrow_forwardA maternal effect gene in Drosophila, called torso, is found as a recessive allele that prevents the correct development of anterior- and posterior-most structures. A wild-type (homozygous) male iscrossed to a female of unknown genotype. This mating produces 100% larva that are missing theiranterior- and posterior-most structures and therefore die during early development. What is the genotype and phenotype of the female fly in this cross? What are the genotypes andphenotypes of the female fly’s parents? Show COMPLETE cross. Maternal genotype:Paternal genotype:F1 genotype:F1 phenotype:arrow_forwardWhat is the difference between a maternal-effect gene and a zygotic gene? Of the following genes that play a role in Drosophila development, which are maternal-effect genes and which are zygotic? Explain your answer. A. nanos B. Antp C. bicoid D. labarrow_forward
- What is positional information? What are three different ways that cells obtain positional information? Which of these ways do you think is the most important for the formation of a segmented body pattern in Drosophila?arrow_forwardImagine a scenario in which prenatal testing of a human female fetus indicates that the baby will have a normal XX karyotype but is heterozygous for a mutation that inactivates the Xist promoter. Allele “Xr” represents the mutated version of the Xist promoter, and “XR” represents the normal version of the Xist promoter. How will this mutation affect the process of X inactivation?A. "X inactivation will still be random with both mutant and normal X chromosomes being randomly inactivated" B. "The chromosome with the mutant Xist promoter will always be active" C. "The chromosome with the mutant Xist promoter will always be inactivated" D. "The normal X chromosome (no mutation in Xist) will always be active" E. "The normal X chromosome (no mutation in Xist) will always be inactivated"arrow_forwardIf the HoxA3 and HoxD3 genesare equivalent, how do you suppose they can play suchdistinct roles in development?arrow_forward
- When an embryo is homozygous mutant for the gap gene Kr, the fourth and fifth stripes of the pair-rule gene ftz (counting from the anterior end) do not form normally. When the gap gene kni is mutant, the fifth and sixth ftz stripes do not form normally. Explain these results in regard to how segment number is established in the embryoarrow_forwardHow do we know that X chromosomal inactivation of either the paternal or maternal homolog is a random event during early development in mammalian females? Select all that apply. a. Studying the electrophoretic variants of glucose-6-phosphate dehydrogenase. b. Using test crosses involving females possessing different genetic markers in sex chromosomes. c. Cytological studying during the blastocyst stage of development. d. Observing the mosaic coat patterns inheritance. e. Using electronic microscopy to track the inactivation of X chromosome.arrow_forwardWhich of the following findings supports the fact that the presence of the Y-chromosome rather than the lack of a second X-chromosome determines the development of maleness in mammals? a. A human with an X0 genotype (Turner syndrome) is phenotypically female. b. A human with an XXY genotype (Klinefelter syndrome) is phenotypically male. c. A transgenic mouse with two X-chromosomes and the SRY gene from the Y-chromosome develops male sex organs. d. b and c, but not a e. a, b, and carrow_forward
- Why is it that mutations in bicoid and nanos exhibit genetic maternal effect in Drosophila (a mutation in the maternal parent produces a phenotype that shows up in the offspring), but mutations in runt and gooseberry do not?arrow_forwardIn marsupials, X inactivation occurs exclusively to paternally derived chromosomes. Which genes will ALWAYS be expressed in this situation? A. maternal X-linked genes B. paternal X-linked genes C. maternal Y-linked genes D. paternal Y-linked genesarrow_forwardIn Drosophila, the genes ct(cut wing margin), y (yellow body), and v (vermilion eye color) are X-linked. Females heterozygous for all three markers were mated with wildtype males and the following male progeny were obtained. As is conventional in Drosophila genetics, the wild-type allele of each gene is designated by a “+” sign in the appropriate column. Use the data to (A) create a genetic map of the genes, (B) calculate interference, and (C) interpret the value of interference. Show your work.arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning