An example of X-linked inheritance First cross Second cross X Y Red female White male White female Red male Male gametes Male gametes Female gametes Female gametes Red temale Red male Red female White male Male gametes Male gametes 0 w Red female Red male Red female Red male Female gametes Female gametes | Red temale i Whte male i White female i White male FIGURE 2-17 Reciprocal crosses between red-eyed (red) and white-eyed (white) Drosophila give different results. The alleles are X linked, and the inheritance of the X chromosome explains the phenotypic ratios observed, which are different from those of autosomal genes. (In Drosophila and many other experimental systems, a superscript plus sign is used to designate the normal, or wild-type, allele. Here, wt encodes red eyes and w encodes white eyes.)

An example of X-linked inheritance First cross Second cross X Y Red female White male White female Red male Male gametes Male gametes Female gametes Female gametes Red temale Red male Red female White male Male gametes Male gametes 0 w Red female Red male Red female Red male Female gametes Female gametes | Red temale i Whte male i White female i White male FIGURE 2-17 Reciprocal crosses between red-eyed (red) and white-eyed (white) Drosophila give different results. The alleles are X linked, and the inheritance of the X chromosome explains the phenotypic ratios observed, which are different from those of autosomal genes. (In Drosophila and many other experimental systems, a superscript plus sign is used to designate the normal, or wild-type, allele. Here, wt encodes red eyes and w encodes white eyes.)

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter4: Pedigree Analysis In Human Genetics

Section: Chapter Questions

Problem 17QP: Analysis of X-Linked Dominant and Recessive Traits A young boy is color-blind. His one brother and...

See similar textbooks

Similar questions

Why are X-linked recessive disorders never passedfrom a father to a son?
Attached are three pedigrees. For each trait, considerwhether it is or is not consistent with X-linked recessiveinheritance. In a sentence or two, indicate why or why not.
Why do X-linked recessive conditions appear most commonlyin males?
Assume that a trait is determined by an X-linked dominant gene. Ifthe mother exhibits the trait but the father does not, then theira. sons are more likely than their daughters to exhibit the trait.b. daughters are more likely than their sons to exhibit the trait.c. sons and daughters are equally likely to exhibit the trait
How many alleles of genesthat condition X-linked traitsdo female and maleindividuals respectivelypresent?
Duchenne muscular dystrophy is a recessive disorder caused by a rare,loss-of-function allele that is located on the X chromosome in humans. Anunaffected woman (i.e., without disease symptoms) who is heterozygousfor the X-linked allele causing Duchenne muscular dystrophy has childrenwith a man with a functional (non-disease-causing) allele. What is theprobability that this couple will have an unaffected son?
A human disease known as vitamin D–resistant rickets isinherited as an X-linked dominant trait. If a male with thedisease produces children with a female who does not have thedisease, what is the expected ratio of affected and unaffectedoffspring?
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) This woman is phenotypically normal. Does thissurprise you? Why or why not? Under what circumstancesmight you expect a phenotypic effect of such arearrangement?
Unattached earlobes (E) are dominant over attached earlobes (e) [Figure (a) and (b)]. If a woman with unattached earlobes and a man with attached earlobes have children, what percentage of their children has the possibility of having unattached earlobes if the mother is homozygous for the trait?
Describe four X-linked recessive disorders
Huntington's disease is caused by a autosomal dominant that is lethal in embryos in the homozygous dominant conditionIf one of your parents has the disease and the other does notwhat is the probability that you will develop the disease? assume if you inherit the Huntington's gene you will get the disease)? 1/4 0 1/2 3/4
All of the following are types of inheritance except Autosomal heterozygous Sex-linked X-Linked Autosomal Dominant