In C. elegans there are two sexes: hermaphrodite and male. Sex is determined by the ratio of X chromosomes to haploid sets of autosomes (X
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Genetic Analysis: An Integrated Approach (3rd Edition)
- The mode of Protenor butterfly sex determination is based on ________. ZW and ZZ for females and males, respectively. XX and XO for hermaphrodites and males, respectively. XX and XY chromosomes for females and males, respectively. XX and XO chromosomes for females and males, respectively. XO and YY chromosomes for females and males, respectively.arrow_forwardPlease DEFINE the following terms, and explain how they apply to Andean Condors: Homogametic sex Heterogametic sexarrow_forwardPlutonian Tickle-bellies have a sex determination system just like mammals. Hairy Snout is a holandric trait (carried on the Y chromosome). MyxRotcccc, a handsome male Tickle-belly, has lovely orange hair on his snout. He and his mate, OrgggWny, have six offspring, three boys and three girls. Please answer the following questions about this family. How many of MyxRotcccc’s and OrgggWny’s offspring have hairy snouts? Can you predict which ones? Their eldest son, Bob, marries and has a son. What is the chance that Bob’s son will also have a hairy snout? JoKchew, MyxRotcccc’s and OrgggWny’s youngest daughter, marries a male who has a smooth, hairless purple snout. She has eight offspring, each one lovelier than the last, and all boys. What percentage of these offspring do you expect to have hairy snouts? Explain.arrow_forward
- Gametogenesis in mammals is a complex process. When comparing spermatogenesis and oogenesis, indicated whether the follow statements are true or false. After the S phase, both the spermatogonial stem cell and primary oocyte have the same number of double-copy chromosomes. #analyze Question 1 options: True False Both the first polar body and the second polar body have the same number of chromosomes. #analyze Question 2 options: True False After the S phase, both the spermatogonial stem cell and primary oocyte have the same number of double-copy chromosomes. #analyze Question 3 options: True False Both the primary oocyte and the secondary spermatocyte have double-copy chromosomes. #analyze Question 4 options: True Falsearrow_forwardIn C. elegans there are two sexes: hermaphrodite and male. Sex is determined by the ratio of X chromosomes to haploid sets of autosomes (X/A). An X/A ratio of 1.0 produces a hermaphrodite (XX), and an X/A ratio of 0.5 results in a male (XO). In the 1970s, Jonathan Hodgkin and Sydney Brenner carried out genetic screens to identify mutations in three genes that result in either XX males (tra-1, tra-2) or XO hermaphrodites (her-1). Double-mutant strains were constructed to assess for epistatic interactions between the genes (see table). Propose a genetic model of how the her and tra genes control sex determination.arrow_forwardAbout 40% of Solomon Islanders carry a gene for blond hair, and yet only 5%–10% of these people actually have blond hair. Why is the number of people with blond hair only 5%–10% when so many people carry genes for blond hair? The duck-billed platypus has a unique mechanism of sex determination: females have five pairs of X chromosomes (X1X1X2X2X3X3X4X4X5X5) and males have five pairs of X and Y chromosomes (X1Y1X2Y2X3Y3X4Y4X5Y5). Do you think each of the X and Y chromosome pairs in males assort independently of other X and Y pairs during meiosis? Why or why not? How is the inheritance of X-linked traits different from the inheritance of autosomal traits? How is the inheritance of X-linked and autosomal traits similar? List as many differences and similarities as you can.arrow_forward
- In certain salamanders, the sex of a genetic female can be altered, changing her into a functional male; these salamanders are called sex reversed males. When a sex-reversed male is mated with a normal female, approximately 23 of the offspring are female and 13 are male. How is sex determined in these salamanders? Explain the results of this crossarrow_forwardUsing this information, how do I figure out the answer to question1? INTRODUCTION In most species of Drosophila, a female mating with a single male usually supplies sufficient sperm to fertilize her lifetime supply of eggs. Moreover, mating is often costly to female flies. So why do females of some species mate more than once? Perhaps they do this to assess the quality of males and/or the sperm males produce via sperm competition. Tom Price, Nina Wedell, and their colleagues at the University of Exeter provide evidence for the sperm competition hypothesis. They show multiple mating increases in frequency when a selfish genetic element that reduces sperm quality is prevalent. In Drosophila, females are XX and males are XY. They normally occur in equal numbers. In D. pseudoobscura, males that harbor the X-linked selfish genetic element sex ratio (SR) have produced nearly all female progeny, as SR sabotages Y-bearing sperm. The SR element gains a tremendous transmission advantage but…arrow_forwardButterflies have an X-Y sex-determination system that is different from that of flies or humans. Female butterflies may be either XY or X0, while butterflies with two or more X chromosomes are males. This photograph shows a tiger swallowtail gynandromorph, which is half male (left side) and half female (right side). Given that the first division of the zygote divides the embryo into the future right and left halves of the butterfly, propose a hypothesis that explains how nondisjunction during the first mitosis might have produced this unusual-looking butterfly. Question is also in the picture.arrow_forward
- The mouse haploid genome contains about 2.9 × 109 nucleotide pairs of DNA. Indicate how many nucleotide pairs of DNA are present in each of the following mouse cells: (a) somatic cell, (b) sperm cell, (c) fertilized egg,(d) primary oocyte, (e) first polar body, (f) secondary spermatocyte.arrow_forwardHow many chromosomes does Drosophila melanogaster have?arrow_forwardOrganisms have the following genotypes. What types of gametes will these organisms produce, and in what proportions?a. Aabbb. AABbc. AaBb Given the following matings, what are the predicted phenotypic ratios of the offspring? Use a branch diagram to show the phenotypic ratio. a. AABb x Aabbarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning