Human Biology (MindTap Course List)
11th Edition
ISBN: 9781305112100
Author: Cecie Starr, Beverly McMillan
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
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?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
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?
A man who is a carrier of a translocated 15/21 chromosome marries a genotypically normal woman.
a. Show the possible gametes that will be formed by this man if the translocated 15/21 chromosome synapses with chromosome 21 at Prophase I.
Researchers 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?)
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...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- Drosophila, 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_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: In Drosophila, yellow body is due to an X-linked gene that is recessive to the gene forgray body.(a) A homozygous gray female is crossed with a yellow male. The F1 are intercrossed toproduce F2. Give the genotypes and phenotypes, along with the expected proportions, of theF1 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 F2progeny.(c) A yellow female is crossed with a gray male. The F1 females are backcrossed with graymales. Give the genotypes and phenotypes, along with the expected proportions, of the F2progeny.(d) If the F2 flies in part b mate randomly, what are the expected phenotypic proportions offlies in the F3??arrow_forward
- A young couple is planning to have children. Knowing that there have been a substantial number of stillbirths, miscarriages, and fertility problems on the husband’s side of the family, they see a genetic counselor. A chromosome analysis reveals that, whereas the woman has a normal karyotype, the man possesses only 45 chromosomes and is a carrier of a Robertsonian translocation between chromosomes 22 and 13. a. List all the different types of gametes that might be produced by the man. b. What types of zygotes will develop when each of gametes produced by the man fuses with a normal gamete produced by the woman? c. If trisomies and monosomies entailing chromosomes 13 and 22 are lethal, approximately what proportion of the surviving offspring are expected to be carriers of the translocation?arrow_forward. Researchers 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.arrow_forwardAn individual heterozygous for a reciprocal translocation possesses the following chromosomes: A B • C D E F G A B • C D V W X R S • T U E F G R S • T U V W X a. Draw the pairing arrangement of these chromosomes in prophase I of meiosis. b. Diagram the alternate, adjacent-1, and adjacent-2 segregation patterns in anaphase I of meiosis. c. Give the products that result from alternate, adjacent-1, and adjacent-2 segregation.arrow_forward
- Choose correct option and do explain. Considering an X-linked dominant trait, if an affected woman and an unaffected man decide to have children, which of the answer choices is possible for their children? a. All of their sons are expected to show the dominant trait. b. Their daughters are expected be heterozygous for the gene. c. Their daughters are not expected to show the dominant trait. d. Their sons are expected to be heterozygous for the gene. e. All their children, whether male or female, are expected to show the dominant trait.arrow_forwardXX individuals can be sex-reversed males if one of their X chromosomes contains a translocated portion of the Y chromosome that includes the SRY gene. In light of what you now know about X-chromosome inactivation, it seems that this karyotype might have more complex consequences. In fact, although most such males are completely sex-reversed, X-chromosome inactivation can cause some of these XX males to have varying degrees of residual female characteristics. a. X-chromosome inactivation in normal XX embryos occurs earlier in development than SRY production in normal XY embryos. When present on a translocation X chromosome, SRY is subject to inactivation. Formulate a hypothesis to explain why many XX individuals with a translocation X chromosome that includes the SRY gene are not completely sex-reversed (male). b. Based on your answer to part (a), why do you think some individuals with this karyotype are completely sex-reversed?arrow_forwardBarr bodies are formed to adjust X chromosome dosage in species other than humans, such as Drosophila (fruit flies) and C. elegans (nematodes). True or False ?arrow_forward
- A woman with no phenotype is known to have a 14:21 translocation. 1. With respect to only chromosomes 14 and 21, how many distinct chromosome combinations will happen in her eggs? What portion will be viable? 2. If she has children with a normal man (no translocations), what is the probability that they have a daughter with Down Syndrome or a son with no phenotype?arrow_forwardAn individual is heterozygous for a reciprocal translocation, with the following chromosomes: A • B C D E F A • B C V W X R S T • U D E F R S T • U V W X a. Draw a picture of these chromosomes pairing in prophase I of meiosis. b. Draw the products of alternate, adjacent-1, and adjacent-2 segregations. c. Explain why the fertility of this individual is likely to be less than the fertility of an individual without a translocation.arrow_forward3) A. How are the following proteins involved in cell division: condensing, cohesin, kinetochore complex, tubulin? B. Why does phenotype not always reveal genotype? C. How can Mendel's postulates of segregation and independent assortment be explained by meiosis? D. Explain the genotypic and phenotypic ratios predicted when performing a monohybrid and a dihybrid cross of heterozygotes? E. How can you use the product rule and sum rule to calculate the probability of a particular genotype resulting from crossing parents of specific genotypes?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning
Biology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning
Human Biology (MindTap Course List)
Biology
ISBN:9781305112100
Author:Cecie Starr, Beverly McMillan
Publisher:Cengage Learning
Biology: The Unity and Diversity of Life (MindTap...
Biology
ISBN:9781305073951
Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr
Publisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
Mitochondrial mutations; Author: Useful Genetics;https://www.youtube.com/watch?v=GvgXe-3RJeU;License: CC-BY