Concept explainers
CASE STUDY | Timing is everything
A man in his early 20s received chemotherapy and radiotherapy as treatment every 60 days for Hodgkin disease. After unsuccessful attempts to have children, he had his sperm examined at a fertility clinic, upon which multiple chromosomal irregularities were discovered. When examined within 5 days of a treatment, extra chromosomes were often present or one or more chromosomes were completely absent. However, such irregularities were not observed at day 38 or thereafter.
Do you think that exposure to chemotherapy and radiotherapy of a spermatogonium would cause more problems than exposure to a secondary spermatocyte?
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Modified Mastering Genetics with Pearson eText -- Standalone Access Card -- for Essentials of Genetics (9th Edition)
- Discuss Concepts One of the human chromosome pairs carries a gene that influences eye color. In an individual human, one chromosome of this pair has an allele of this gene that contributes to the formation of blue eyes. The other chromosome of the pair has an allele that contributes to brown eye color (other genes also influence eye color in humans). After meiosis in the cells of this individual, what fraction of the nuclei will carry the allele that contributes to blue eyes? To brown eyes?arrow_forwardEqualizing the Expression of X Chromosome Genes in Males and Females Individuals with an XXY genotype are sterile males. If one X is inactivated early in embryogenesis, the genotype of the individual effectively becomes XY. Why will this individual not develop as a normal male?arrow_forwardHi, could your please answer this question? I'm so confused. The following diagram (picture added) shows 2 pairs of autosomal chromosomes in a karyotype of a biological woman. Based on the karyotype, a genetic counselor determined that there is evidence that a translocation occurred between two non-homologous chromosomes. The other 21 pairs of chromosomes are NOT shown in this diagram. Assume no chromosomal aberrations occurred in the other chromosomes. As a student-researcher, what would be your answer if the genetic counselor asks you if you can determine whether the translocation occurred in a somatic cell, germ-line cell, or whether this can even be determined from the figure? provide the reasoning for your answer.arrow_forward
- 1. Maurice was born with an XY chromosome type, and he has the external genitalia of a male. He has, for the better part of his life, however, felt like he was supposed to be a woman. He has always identified more with feminine clothes, behaviors, and emotions. According to chapter 10 in your textbook, Maurice has a male __________. 2. Maurice was born with an XY chromosome type, and he has the external genitalia of a male. He has, for the better part of his life, however, felt like he was supposed to be a woman. He has always identified more with feminine clothes, behaviors, and emotions. According to chapter 10 in your textbook, Maurice has a female __________. 3. __________ is a biological phenomenon, while __________ is a socially constructed phenomenon. 4. A young boy develops facial and chest hair, pubic hair, and an enlarged Adam’s apple. This happens because puberty is stimulating the development of his ______.arrow_forwardExplain why a person with Klinefelter Syndrome (XXY) still exhibits abnormal phenotypes despite the fact that one of the extra X Chromosome is inactivated practically leaving an XY active sex chromosomes similar to a normal male?arrow_forwardpolygenic trait mating 2 An AaBBCcdd male mates with an AaBbCCDD female. 1. What is the maximum number of ridge-producing genes possible in one of the children? 2. What would be the TRC for this child if it is a male? 3. What is the minimum number of ridge-producing genes possible in a child of this couple? 4. If this child were a female, would she have a higher or lower TRC than the parent with the lower ridge count? A. lower B. higher C. equalarrow_forward
- 2. Healthy elephant somatic cells are 2n=56. How many chromosomes are in a daughter cell at the beginning of MEIOSIS II in elephants? Group of answer choices A. 28 un-replicated B. 28 replicated C. 56 un-replicated D. 56 replicated 3. While studying tumor cells, you notice that the histones of a particular chromosome have more acetyl groups bound to them in tumor cells, compared to the same chromosome in healthy cells. What would you expect for the amount of proteins encoded by genes on that chromosome in tumor cells compared to healthy cells? Group of answer choices A. Higher in tumor cells B. Lower in tumor cells C. Similar in tumor and healthy cellsarrow_forwardA company that offers PGD terms an embryo “normal and healthy” if it has 46 chromosomes. Why is this statement misleading? , Two famous male actors had twins using a surrogate mother who carried two embryos that hadbeen fertilized in vitro, one with one man’s sperm and the other with the other man’s sperm. In terms of genetics, how closely are the babies, a boy and a girl, related to each other if they have different fathers?arrow_forward1) What is Dosage compensation as it relates to sex chromosomes 2) What is the Lyon's Hypothesis--Who is Mary Lyon's 3) What is a Calico Cat? and How does one of these cats look and What has happened to their X chromosomes to make them look that way. IN YOUR OWN WORDS PLEASE NOT COPY PASTEarrow_forward
- 4) Explain why you can NOT typically have a Male Calico cat. 5) Can you think of any unusual situation where you might be able to have a Male Calico cat? Explain how this might occur 6) Explain how X chromosome inactivation takes place in mammals at the chromosomal and molecular level. B. What genes are involved in inactivating a human X chromosome? C. What role does X chromosome-specific inactivating transcript --XIST-- non coding RNA play in the inactivation of the human X chromosome.arrow_forwardX chromosome inactivation in a diploid XX female is not completely inactivated, explain?arrow_forwardAt the end of Meiosis II in human cells (specifically in males, for example), how many gametes are made from one original parent cell, how many chromosomes are in each gamete, and what is each chromosome made of (that is, if you compared, say, chromosome #1 in a gamete with the two #1 chromosomes the person inherited from his parents)?arrow_forward
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