The reason which makes calico cats almost invariably female. Introduction: Females have two X chromosomes due to which they have two copies of all the genes present on that chromosome whereas males carry only one copy of X chromosome due to which they have only one copy of the gene present on that chromosome. All female mammals contain a genetically inactive X chromosome which is known as the Barr body. The expression of gene products by the genes present on the X chromosome is equalized in both males and the females.

Question

Want to see the full answer?

Answer 1

Question

Chapter 7, Problem 16QP

Summary Introduction

To determine: The reason which makes calico cats almost invariably female.

Introduction: Females have two X chromosomes due to which they have two copies of all the genes present on that chromosome whereas males carry only one copy of X chromosome due to which they have only one copy of the gene present on that chromosome. All female mammals contain a genetically inactive X chromosome which is known as the Barr body. The expression of gene products by the genes present on the X chromosome is equalized in both males and the females.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

Cat fur coat color genetics is interesting. Orange fur is dominant (''B'') to black fur (''b'') and piebald, which is white spotting, is dominant (''S'') to non-white-spotted (''s''). Both of those genes are located on the X chromosome. In addition, in cats, somatic cells exhibit X-inactivation randomly, which explains why there are tortoiseshell cats (when heterozygous, have orange and black spots) as well as calico cats (orange and black but also with white spots). An orange and white spotted male is mated with a tortoiseshell female. State the genotype of the male and the female.

Cat fur coat color genetics is interesting. Orange fur is dominant (''B'') to black fur (''b'') and piebald, which is white spotting, is dominant (''S'') to non-white-spotted (''s''). Both of those genes are located on the X chromosome. In addition, in cats, somatic cells exhibit X-inactivation randomly, which explains why there are tortoiseshell cats (when heterozygous, have orange and black spots) as well as calico cats (orange and black but also with white spots). An orange and white spotted male is mated with a tortoiseshell female. Draw a dihybrid Punnet square to show the possible offspring:

mapping gene The genes for ruby eyes (rb), tan body (t) and cut wings (ct) are all found on the X-chromosome of Drosophila melanogaster. All of these are recessive traits. They map in the order rb, ct, t with 12.5 map units between rb and ct and 7.5 map units between ct and t. Suppose you cross a cut wing male with a homozygous female that is both tan and has ruby eyes. What will the F1 females look like? Draw map of the section of the X chromosomes that has these 3 genes for the F1 females Assume you testcross your F1 females. What progeny classes would you expect? ii. Give approximate numbers for each class based on a total of 2000 progeny. Assuming the i=1 and there are no double crossovers. Assuming the i=0 and there are the expected number of double crossovers.