Patients with Down syndrome have three copies of chromosome 21, resulting in characteristics like a small head with a flat face and small ears, a short neck, a bulging tongue, upward slant eyes, and impaired development of the nervous system. Why does a patient with Down syndrome have these characteristics? O due to reduced expression of genes resulting from missing genetic information O due to the overproduction of proteins resulting from extra genetic information O due to the abnormal multiplication of cells caused by environmental factors O due to mutations in the cells of the patient caused by environmental factors

Patients with Down syndrome have three copies of chromosome 21, resulting in characteristics like a small head with a flat face and small ears, a short neck, a bulging tongue, upward slant eyes, and impaired development of the nervous system. Why does a patient with Down syndrome have these characteristics? O due to reduced expression of genes resulting from missing genetic information O due to the overproduction of proteins resulting from extra genetic information O due to the abnormal multiplication of cells caused by environmental factors O due to mutations in the cells of the patient caused by environmental factors

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter6: Cytogenetics: Karyotypes And Chromosome Aberrations

Section: Chapter Questions

Problem 17QP

See similar textbooks

Similar questions

Fragile-X syndrome causes the most common form of inherited intellectual disability. What is the chromosomal abnormality associated with this disorder? What is the phenotype of this disorder?
Red–green color blindness in humans is due to an X-linked recessive gene. A woman whose father is color blind possesses one eye with normal color vision and one eye with color blindness. a. Propose an explanation for this woman’s vision pattern. Assume that no new mutations have spontaneously arisen. b. Would it be possible for a man to have one eye with normal color vision and one eye with color blindness?
Which, if any, of the following statements is false? a) Most of the inherited changes in our DNA arise because of exposure to extracellular mutagens, including radiation sources and chemical mutagens. b) Most of the inherited changes in our DNA arise because of unavoidable endogenous errors in cellular mechanisms and harmful effects of certain natural molecules and atoms within our cells. c) Errors in DNA replication and DNA repair are a major source of mutations in our cells. d) Significant chemical damage is sustained by DNA because of its proximity to water molecules in our cells.
Fathers contribute more new point mutations to theirchildren than mothers. You may know from general biology that people have sex chromosomes—two X chromosomes in females and an X plus a Y chromosome inmales. Both sexes have the autosomes (A’s).a. On which type of chromosome (A, X, or Y) wouldyou expect the genes to have the greatest number ofnew mutations per base pair over many generations ina population? Why?b. On which type of chromosome would you expect theleast number of new mutations per base pair? Why?c. Can you calculate the expected number of newmutations per base pair for a gene on the X and Ychromosomes for every one new mutation in a geneon an autosome if the mutation rate in males is twicethat in females?
When mice carrying the Avy allele exhibit a darker coat, thisphenotype is thought to be caused by dietary factors thatresult ina. a greater level of DNA methylation and a decrease in theexpression of the Agouti gene.b. a lower level of DNA methylation and a decrease in theexpressionof the Agouti gene.c. a greater level of DNA methylation and the overexpressionof the Agouti gene.d. a lower level of DNA methylation and the overexpression ofthe Agouti gene.
Red–green color blindness in humans is due to an X-linked recessive gene. A woman whose father is color blind possesses one eye with normal color vision and one eye with color blindness. Q. Propose an explanation for this woman’s vision pattern. Assume that no new mutations have spontaneously arisen.
Let’s suppose an X-linked gene in mice exists as two alleles, whichwe will call B and b. X-chromosome inactivation, a process inwhich one X chromosome is turned off, occurs in the somatic cellsof female mammals . Allele B encodes an mRNA that is 900 nucleotides long, whereas allele b contains a small deletion that shortens the mRNA to a length of 825 nucleotides.Draw the expected Northern blot that will be obtained usingmRNA isolated from somatic tissue of the followingmice:Lane 1. mRNA from an XbY male mouseLane 2. mRNA from an XbXb female mouseLane 3. mRNA from an XBXb female mouse.Note: The sample taken from the female mouse is not from aclone of cells. It is from a tissue sample, like the one shown.
Interested in exploring the genetic pathways that lead to neurological issues, you want to see if recessive mutations which generate too many neurons (tm) in flies - which many causes autistic like symptoms are in the same gene as mutations that generate too few neurons (tf) - intellectual diabilities. You cross a true-breeding homozygous tm/tm fly to a homozygous too few neuron fly tf/tf. What phenotype in the progeny would tell these mutations are in different genes?
researchers have been able to clonemammals by fusing a cell having a diploid nucleus (i.e., a somaticcell) with an egg that has had its nucleus removed.A. With regard to maternal effect genes, would the phenotype ofsuch a cloned animal be determined by the animal that donatedthe egg or by the animal that donated the somatic cell? Explain.B. Would the cloned animal inherit extranuclear traits from theanimal that donated the egg or from the animal that donated thesomatic cell? Explain.C. In what ways would you expect this cloned animal to be similarto or different from the animal that donated the somatic cell? Isit fair to call such an animal a clone of the animal that donatedthe diploid nucleus?
Having a mutant form of the gene XYZ is associated with a higher incidence of cancer than is seen in the general population. If mutant XYZ runs in a woman’s family, will she automatically get cancer? Explain why or why not.
What is mutation? Distinguish between (i) neutral and silent mutation (ii) germ line and somatic mutation (iii) Trisomy 21 and Trisomy X
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?