Concept explainers
A healthy couple with a history of three previous spontaneous abortions has just had a child with
Are the chromosomes in the child consistent with those expected in a case of
Which parent has an abnormal karyotype? How can you tell? What is the nature of the abnormality?
Why does this parent have a normal
Diagram the pairing of the abnormal chromosomes.
What segregation pattern occurred to produce the gamete involved in fertilization of the child with
What is the approximate probability that the next child of this couple will have
Do the karyotypes of the parents help explain the occurrence of the three previous spontaneous abortions? Explain.
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Genetic Analysis: An Integrated Approach (3rd Edition)
- 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?arrow_forwardA normal female is discovered with 45 chromosomes, one of which exhibits a Robertsonian translocation containing most of chromosomes 15 and 21. Discuss the possible outcomes in her offspring when her husband contains a normal karyotype.arrow_forward2 3 4 5 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 ху Which chromosome set has an extra What diagnosis would you give this patient?. Finish the notation for this patient's karyotype: What causes a dark band on the chromosome? What is a centromere?arrow_forward
- Chorionic villus sampling is a procedure to determine if there are any abnormalities in chromosome number in the fetus. Why can the chorionic villi be used to determine abnormalities in the fetus?arrow_forwardA 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. List all the different types of gametes that might be produced by the man.arrow_forwardDuring the pathoanatomic inspection of a baby-boy's dead body the following abnormalities: polydactily, microcephaly, a cleft lip and cleft palate, hypertrophy of the parenchymal organs were found. These symptoms are typical of Patau syndrome. What is the cause of this disease? Select one: a. Trisomy on the 21st chromosome. O b. Trisomy on the 18th chromosome. c. Trisomy on the 13th chromosome. d. Trisomy on X chromosome. e. Monosomy on X chromosome.arrow_forward
- In a sample of 1000 patients with Down syndrome, a geneticist discovers that 95% of them are trisomic, while 5% have diploid number of chromosomes. Explain this discrepancy.arrow_forwardFamilial Down syndrome is similar to primary Down syndrome in that it is caused by trisomy 21. However, in familial Down syndrome, all or part of the third copy of chromosome 21 has translocated onto another autosome, typically chromosome 14. In cases of familial Down syndrome, one of the parents of the affected child is often a carrier of a translocated chromosome. The translocation carrier parent does not have Down syndrome because he or she has a total of two copies of chromosome 21. Suppose that a woman is a translocation carrier of chromosome 21 on chromosome 14. She conceives six zygotes with a man who carries no aneuploidies. Match the description of the chromosomes inherited by each zygote with the viability and phenotype of the zygote. ✓ Two normal copies of 14, two normal copies of 21 two normal copies of 21, one normal copy of 14 ✓one normal copy of 14, one 21 to 14 translocation, one normal copy of 21 ✓two normal copies of 14, one normal copy of 21, on 21 to 14…arrow_forwardA girl and a boy were born to a young married couple. The girl is absolutely healthy. The examination of the boy's karyotype has shown 46 chromosomes. But one of the chromosomes of the 15th pair is longer than normal as a part of a chromosome from the 21st pair has joined it. How many autosomes and sex chromosomes are in the boy's karyotype? Name the type of the mutation. Is it possible to consider this pathology an inherited disorder?arrow_forward
- 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.arrow_forwardA 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_forwardFrom 2 to 6 percent of people with autism have an extra chromosome that consists of two long arms of chromosome 15. It includes two copies of the chromosome 15 centromere. Two normal copies of the chromosome are also present. What type of chromosome abnormality in a gamete can lead to this karyotype, which is called isodicentric 15?arrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning