Human Heredity: Principles and Issues (MindTap Course List)
11th Edition
ISBN: 9781305251052
Author: Michael Cummings
Publisher: Cengage Learning
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Chapter 6, Problem 19QP
The majority of nondisjunction events leading to Down syndrome are maternal in origin. Based on the duration of meiosis in females, speculate on the possible reasons for females contributing aneuploid gametes more frequently than males do.
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Though an individual with abberations such as Robertsonian translocation may be phenotypically normal, they can generate gametes through meiosis that have atypical organizations of chromosomes, resulting in recurrent fetal abnormalities or miscarriages. Why, despite these Robertsonian translocations, are affected cells still able to generate typical gametes through meiosis?
Why does nondisjunction in meiosis I results in a higher proportion of faulty gametes than nondisjunction in meiosis II?
Please explain the outcomes of nondisjunction in meiosis one versus nondisjunction in meiosis two, in terms of the effect on the gametes. Please give an example of a defect that results from nondisjunction in meiosis.
Chapter 6 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
Ch. 6 - Genetics in Practice case studies are...Ch. 6 - Genetics in Practice case studies are...Ch. 6 - Analyzing Karyotypes 1. Originally, karyotypic...Ch. 6 - Given the karyotype shown at right, is this a male...Ch. 6 - A colleague e-mails you saying that she has...Ch. 6 - What are the two most commonly used methods of...Ch. 6 - Prob. 5QPCh. 6 - Discuss the following sets of terms: a. trisomy...Ch. 6 - What chromosomal abnormality can result from...Ch. 6 - Tetraploidy may result from: a. lack of...
Ch. 6 - A cytology student believes he has identified an...Ch. 6 - An individual is found to have some tetraploid...Ch. 6 - A spermatogonial cell undergoes mitosis before...Ch. 6 - A teratogen is an agent that produces nongenetic...Ch. 6 - As a physician, you deliver a baby with protruding...Ch. 6 - Variations in Chromosome NumberAneuploidy Describe...Ch. 6 - A woman gives birth to monozygotic twins. One boy...Ch. 6 - Assume that a meiotic-nondisjunction event causes...Ch. 6 - Prob. 17QPCh. 6 - What is the genetic basis and phenotype for each...Ch. 6 - The majority of nondisjunction events leading to...Ch. 6 - Prob. 20QPCh. 6 - If all the nondisjunction events leading to Turner...Ch. 6 - Identify the type of chromosomal aberration...Ch. 6 - Describe the chromosomal alterations and phenotype...Ch. 6 - A geneticist discovers that a girl with Down...Ch. 6 - Albinism is caused by an autosomal recessive...Ch. 6 - Fragile-X syndrome causes the most common form of...
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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
- Assume 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_forwardProvide two reasons why meiosis leads to genetic variation in diploid organisms.arrow_forwardDescribe the chromosomal alterations and phenotype of cri du chat syndrome and Prader-Willi syndrome.arrow_forward
- Sex chromosome aneuploidy is usually welltolerated because only one X chromosomeremains __________ and because the Y chromosomehas few genes.arrow_forwardA monosomic G. hirsutum is crossed with G. thurberi and produces offspring, some with 39 chromosomes and some with 38 chromosomes. Using cytological examination at meiosis, the 38-chromosome types show 13 bivalents and 12 univalents. Explain these results by making the pertinent crosses.arrow_forwardWhat can be concluded about the severity of nondisjunction that occurs in meiosis I as opposed to meiosis II?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. Q. What types of zygotes will develop when each of gametes produced by the man fuses with a normal gamete produced by the woman?arrow_forwardWhich is the type ofgamete produced by aheterozygous individual?What is the genotypicalproportion of these gametes?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 Q. Draw the pairing arrangement of these chromosomes in prophase I of meiosis.arrow_forward
- If chromosomal nondisjunction occurs during meiosis I, what proportion of zygotes formed from the resulting gametes would be aneuploid? (Assume the gametes from the other parent are normal)a) 0% b) 25% c) 50% d) 75% e) 100%arrow_forwardAt what stage of meiosis (I or II) does crossing-over occur?arrow_forwardFor each of the following genotypes, what tyoes of gametes will be produced?arrow_forward
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