Human Biology (MindTap Course List)
11th Edition
ISBN: 9781305112100
Author: Cecie Starr, Beverly McMillan
Publisher: Cengage Learning
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Chapter 20, Problem 2CT
Human sex chromosomes are XX for females and XY for males.
- a. With respect to an X-linked gene, how many different types of gametes can a male produce?
- b. If a female is homozygous for an X-linked allele, how many different types of gametes can she produce with respect to this allele?
- c. If a female is heterozygous for an X-linked allele, how many different types of gametes can she produce with respect to this allele?
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Human females have two X chromosomes (XX); males have one X and one Y chromosome (XY). a. With respect to X chromosome alleles, how many different types of gametes can a male produce? b. If a female is homozygous for an allele on an X chromosome, how many types of gametes can she produce with respect to that allele? c. If a female is heterozygous for an X chromosome allele, how many types of gametes can she produce with respect to that allele?
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Chapter 20 Solutions
Human Biology (MindTap Course List)
Ch. 20 - Prob. 1RQCh. 20 - What is a carrier of a genetic trait?Ch. 20 - What evidence indicates that a trait is coded by a...Ch. 20 - Prob. 4RQCh. 20 - Explain what nondisjunction is, and give two...Ch. 20 - _______ segregate during ______. a. Homologues;...Ch. 20 - Prob. 2SQCh. 20 - Genes on the same chromosome tend to stay together...Ch. 20 - Prob. 4SQCh. 20 - A chromosomes structure can be altered by _______....
Ch. 20 - Nondisjunction can be caused by ________. a....Ch. 20 - A gamete affected by nondisjunction could have...Ch. 20 - Genetic disorders can be caused by __________. a....Ch. 20 - A person who is a carrier for a genetic trait...Ch. 20 - Prob. 10SQCh. 20 - If a couple has six boys, what is the probability...Ch. 20 - Human sex chromosomes are XX for females and XY...Ch. 20 - People with Down syndrome have an extra copy of...Ch. 20 - Prob. 4CTCh. 20 - Prob. 5CTCh. 20 - About 4 percent of people of Northern European...Ch. 20 - The following pedigree shows the pattern of...
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- Human females have two X chromosomes XX; males have one X and one Y chromosome XY. a. With respect to X-linked alleles, how many different types of gametes can a male produce? b. A female homozygous for an X-linked allele can produce how many types of gametes with respect to that allele? c. A female heterozygous for an X-linked allele can produce how many types of gametes with respect to that allele?arrow_forwardAssume that a meiotic-nondisjunction event causes trisomy 8 in a newborn. If two of the three copies of chromosome 8 are absolutely identical, at what point during meiosis did the nondisjunction event take place?arrow_forwardA phenotypically normal boy has 45 chromosomes, but his sister, who has Down syndrome, has 46. Suggest an explanation that explains both children.arrow_forward
- Given a cross between AabbCcDdEeFFGgHh x AaBbCcDdEEffggHH, a) how many possible gametes can the first individual produce? b) what proportion of the offspring will phenotypically resemble the first parent? c) what proportion of the offspring will genotypically resemble the second parent? d) how many phenotypes can be expected from the cross?arrow_forwardA certain type of congenital deafness in humans is caused by a rare autosomal (not X-linked) dominant gene. (a) In a mating involving a deaf man and a deaf woman (both heterozygous), would you expect all the children to be deaf? Explain your answer. (b) In a mating involving a deaf man and a deaf women (both heterozygous), could all the children have normal hearing? Explain your answer. (c) Another form of deafness is caused by a rare autosomal recessive gene. In a mating involving a deaf man and a deaf woman, could some of the children have normal hearing? Explain your answer.arrow_forwardIn Drosophila, the X chromosomes may become attached to one another (XXn ) such that they always segregate together. Some flies thus contain a set of attached X chromosomes plus a Y chromosome. (a) What sex would such a fly be? Explain why this is so. (b) Given the answer to part (a), predict the sex of the off-spring that would occur in a cross between this fly and a normal one of the opposite sex. (c) If the offspring described in part (b) are allowed to interbreed, what will be the outcome?arrow_forward
- Table 8.1 shows that Turner syndrome occurs when an individual inherits one X chromosome but lacks a second sex chromosome. Can Turner syndrome be due to nondisjunction during oogenesis, spermatogenesis, or both? If a phenotypically normal couple has a color-blind child (due to a recessive X-linked allele) with Turner syndrome, did nondisjunction occur duringoogenesis or spermatogenesis in this child’s parents? Explain your answer.arrow_forwardResearchers discovered recently that the sole functionof the SRY protein is to activate an autosomal genecalled Sox9 in the presumptive gonad (before it has“decided” to become a testis or an ovary).a. What would be the sex of an XY individual homozygous for nonfunctional mutant alleles of Sox9?Explain.b. Given your answer to part (a), why is SRY, ratherthan Sox9, considered the male determining factor?(Hint: What do you think would happen if you didan experiment like the one in the Fast Forward BoxTransgenic Mice Prove That SRY Is the MalenessFactor, except that you used a Sox9 transgeneinstead of SRY?)arrow_forwardHuman females have two X chromosomes (XX); males have one X and one Y chromosome (XY). a. With respect to X-linked alleles, how many different types of gametes can a male produce? b. If a female is homozygous for an X-linked allele, how many types of gametes can she produce with respect to that allele? c. If a female is heterozygous for an X-linked allele, how many types of gametes can she produce with respect to that allele?arrow_forward
- Given the karyotype shown at right, is this a male or a female? Normal or abnormal? What would the phenotype of this individual be?arrow_forwardIn a cross between a homozygous red-eyed female fruit fly and a white-eyed male fruit fly, what is the expected outcome? a. all white-eyed male offspring b. all white-eyed female offspring c. all red-eyed offspring d. half white-eyed make offspringarrow_forwardGenes A and B are on different chromosomes. An individual has the genotype: AaBb You sequence two gametes produced by this individual and find one gamete has the genotype AB, and one has the genotype Ab. How can this one individual (genotype AaBb) produce two gametes with different genotypes (AB or Ab)? Your answer should describe a specific process which occurs during meiosis. At what stage of meiosis does this process occur?arrow_forward
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