In humans, chromosome 16 sometimes has a heavily stained area near the centromere. This feature can be seen in a microscope, but otherwise has no effect on the phenotype of the person carrying it. When such a “blob" exists on given copy of chromosome 16, it is a constant feature of that chromosome and is inherited. A couple conceived a child, but the fetus had multiple abnormalities and was miscarried. e.g., The fetus had three copies of chromosome 16, where 2 of the 3 copies of chromosome 16 had large blobs. Both of the mother's copies of chromosome 16 lacked blobs, but the father was heterozygous for blobs. The fetus was formed from a fertilization event that included a gamete produced by the in which nondisjunction occurred during the meiotic division. Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a mother; first. mother; second. father; first. C Your answer d father; second. E3 Fullso L e Insufficient information is provided to deduce this answer.

In humans, chromosome 16 sometimes has a heavily stained area near the centromere. This feature can be seen in a microscope, but otherwise has no effect on the phenotype of the person carrying it. When such a “blob" exists on given copy of chromosome 16, it is a constant feature of that chromosome and is inherited. A couple conceived a child, but the fetus had multiple abnormalities and was miscarried. e.g., The fetus had three copies of chromosome 16, where 2 of the 3 copies of chromosome 16 had large blobs. Both of the mother's copies of chromosome 16 lacked blobs, but the father was heterozygous for blobs. The fetus was formed from a fertilization event that included a gamete produced by the in which nondisjunction occurred during the meiotic division. Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a mother; first. mother; second. father; first. C Your answer d father; second. E3 Fullso L e Insufficient information is provided to deduce this answer.

Human Biology (MindTap Course List)

11th Edition

ISBN:9781305112100

Author:Cecie Starr, Beverly McMillan

Publisher:Cecie Starr, Beverly McMillan

Chapter20: Chromosomes And Human Genetics

Section: Chapter Questions

Problem 3CT: People with Down syndrome have an extra copy of chromosome 21, for a total of 47 chromosomes....

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People with Down syndrome have an extra copy of chromosome 21, for a total of 47 chromosomes. However, in a few cases of Down syndrome, 46 chromosomes are present. This total includes two normal-looking chromosomes 21, one normal chromosome 14, and a longer-than-normal chromosome 14. Interpret this observation. How can these individuals have 46 chromosomes?
A woman with an abnormally long chromosome 13 (and a normalhomolog of chromosome 13) has children with a man with anabnormally short chromosome 11 (and a normal homolog of chromosome 11). What is the probability of producing an offspringthat will have both a long chromosome 13 and a short chromosome11? If such a child is produced, what is the probability that thischild will eventually pass both abnormal chromosomes to one ofhis or her offspring?
The karyotype of a young girl who is affected with familialDown syndrome revealed a total of 46 chromosomes. Her olderbrother, however, who is phenotypically unaffected, actually had45 chromosomes. Explain how this could happen. What wouldyou expect to be the numbers of chromosomes in the parents ofthese two children?
A rare form of dwarfism that also included hearing loss was foundto run in a particular family. It is inherited as a dominant trait. Itwas discovered that an affected individual had one normal copy ofchromosome 15 and one abnormal copy of chromosome 15 thatwas unusually long. How would you determine if the unusuallylong chromosome 15 was causing this disorder?
A couple planning their family are aware that through the pastthree generations on the husband’s side a substantial numberof stillbirths have occurred and several malformed babies wereborn who died early in childhood. The wife has studied geneticsand urges her husband to visit a genetic counseling clinic,where a complete karyotype-banding analysis is performed.Although the tests show that he has a normal complement of46 chromosomes, banding analysis reveals that one memberof the chromosome 1 pair (in group A) contains an inversioncovering 70 percent of its length. The homolog of chromosome1 and all other chromosomes show the normal bandingsequence. Question: How would you explain the high incidence of paststillbirths?
A couple planning their family are aware that through the pastthree generations on the husband’s side a substantial numberof stillbirths have occurred and several malformed babies wereborn who died early in childhood. The wife has studied geneticsand urges her husband to visit a genetic counseling clinic,where a complete karyotype-banding analysis is performed.Although the tests show that he has a normal complement of46 chromosomes, banding analysis reveals that one memberof the chromosome 1 pair (in group A) contains an inversioncovering 70 percent of its length. The homolog of chromosome1 and all other chromosomes show the normal bandingsequence. Question: What can you predict about the probability of abnormality/normality of their future children?
Genes that cause Prader-Willi syndrome and Angelman syndromeare closely linked along chromosome 15. Although people withthese syndromes do not usually reproduce, let’s suppose that acouple produces two children with Angelman syndrome. The oldest child (named Pat) grows up and has two children with PraderWilli syndrome. The second child (named Robin) grows up andhas one child with Angelman syndrome.A. Are Pat and Robin’s parents both phenotypically normal ordoes one of them have Angelman or Prader-Willi syndrome? Ifone of them has a disorder, state whether it is the mother or thefather, and explain how you know.B. What are the sexes of Pat and Robin? Explain.
Genes that cause Prader-Willi syndrome and Angelman syndromeare closely linked along chromosome 15. Although people withthese syndromes do not usually reproduce, let’s suppose that acouple produces two children with Angelman syndrome. The oldestchild (named Pat) grows up and has two children with Prader-Willi syndrome. The second child (named Robin) grows up andhas one child with Angelman syndrome.A. Are Pat and Robin’s parents both phenotypically normal ordoes one of them have Angelman or Prader-Willi syndrome? Ifone of them has a disorder, state whether it is the mother or thefather, and explain how you know.B. What are the sexes of Pat and Robin?
A couple planning their family are aware that through the past threegenerations on the husband's side a substantial number of stillbirthshave occurred and several malformed babies were born who diedearly in childhood. The wife has studies genetics and urges herhusband to visit a genetic counseling clinic, where a completekaryotype-banding analysis is performed. Although the tests showthat he has a normal complement of 46 chromosomes, bandinganalysis reveals that one member of the chromosome 1 pair (ingroup A) contains an inversion covering 70 percent of its length.The homolog of chromosome 1 and all other chromosomes showthe normal banding sequence.(a) How would you explain the high incidence of past stillbirths?predictabouttheprobabilityof(b) What can you abnormality/normality of their future children?(c) Would you advise the woman that she will have to bring each pregnancy to term to determine whether the fetus is normal? Ifnot, what else can you suggest?
On rare occasions, people are born with a condition known as uniparental disomy. It happens when an individual inherits both copies of achromosome from one parent and no copies from the other parent. Thisoccurs when two abnormal gametes happen to complement each otherto produce a diploid zygote. For example, an abnormal sperm thatlacks chromosome 15 could fertilize an egg that contains two copies ofchromosome 15. In this situation, the individual has maternal uniparental disomy 15 because both copies of chromosome 15 were inheritedfrom the mother. Alternatively, an abnormal sperm with two copies ofchromosome 15 could fertilize an egg with no copies. This is known aspaternal uniparental disomy 15. If a female is born with paternal uniparental disomy 15, would you expect her to be phenotypically normal,have Angelman syndrome (AS), or have Prader-Willi syndrome(PWS)? Explain. Would you expect her to produce normal offspring oroffspring affected with AS or PWS?
A woman who sought genetic counseling is found to be heterozygousfor a chromosomal rearrangement between the second andthird chromosomes. Her chromosomes, compared to those in anormal karyotype, are diagrammed on the next page:(a) What kind of chromosomal aberration is shown?
Why is a chromosome with two centromeres (adicentric chromosome) unstable? Would a backup cen-tromere not be a good thing for a chromosome, giving ittwo chances to form a kinetochore and attach to microtu-bules during mitosis? Would that not help to ensure thatthe chromosome did not get left behind at mitosis?