Sex-Linked Traits Most traits of the human genome are autosomal traits, which means the alleles for...
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Sex-Linked Traits Most traits of the human genome are autosomal traits, which means the alleles for these traits are located on pairs 1 –22. Some traits are inherited on the "X" chromosome of the 23rd pair of sex chromosomes. The "Y" chromosome carries NO alleles for any traits. The trait for colorblindness is caused by a recessive allele on the "X" chromosome. The allele for normal vision is "C" and is dominant over the recessive allele "c".
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Transcript of Sex-Linked Traits Most traits of the human genome are autosomal traits, which means the alleles for...
Sex-Linked Traits
Most traits of the human genome are autosomal traits, which means the alleles for these traits are located on pairs 1 –22.
Some traits are inherited on the "X" chromosome of the 23rd pair of sex chromosomes. The "Y" chromosome carries NO alleles for any traits.
The trait for colorblindness is caused by a recessive allele on the "X" chromosome. The allele for normal vision is "C" and is dominant over the recessive allele "c".
The answer is 12, people with abnormal vision see 45
The answer is 15, people with abnormal vision see 76
The answer is 6, people with abnormal vision see 8.
The answer is 73, people with abnormal vision see 18.
Trait: Colorblindness Alleles: C =normal vision c = colorblind
Genotypes PhenotypesXC XC Female w/normal vision_XC YXc Xc
XC Xc
(Known as a “ ".)Xc Y
Trait: Colorblindness Alleles: C =normal vision c = colorblind
Genotypes PhenotypesXC XC Female w/normal vision_XC Y Male w/ normal visionXc Xc
XC Xc
(Known as a “ ".)Xc Y
Trait: Colorblindness Alleles: C =normal vision c = colorblind
Genotypes PhenotypesXC XC Female w/normal vision_XC Y Male w/ normal visionXc Xc Colorblind FemaleXC Xc
(Known as a “ ".)Xc Y
Trait: Colorblindness Alleles: C =normal vision c = colorblind
Genotypes PhenotypesXC XC Female w/normal vision_XC Y Male w/ normal visionXc Xc Colorblind FemaleXC Xc Female w/ normal vision
(Known as a “carrier".)Xc Y
Trait: Colorblindness Alleles: C =normal vision c = colorblind
Genotypes PhenotypesXC XC Female w/normal vision_XC Y Male w/ normal visionXc Xc Colorblind FemaleXC Xc Female w/ normal vision
(Known as a “carrier".)Xc Y Colorblind male
Sample Problems
Normal man (___ ___) & Carrier woman (___ ___)
What % of offspring will be normal? ____ Colorblind? ______What % of the females will be normal? ____ Colorblind? _____What % of the males will be normal? _____ Colorblind? _____What % will be carriers? _________If they have a daughter, what is the chance she will be a carrier?_____
Sample Problems
Colorblind man (___ ___) & Normal woman (___ ___)
What % of offspring will be normal? ____ Colorblind? ______What % of the females will be normal? ____ Colorblind? _____What % of the males will be normal? _____ Colorblind? _____What % will be carriers? _________If they have a daughter, what is the chance she will be colorblind?_____
Sample Problems
Normal man (___ ___) & Colorblind woman (___ ___)
What % of offspring will be normal? ____ Colorblind? ______What % of the females will be normal? ____ Colorblind? _____What % of the males will be normal? _____ Colorblind? _____If they have a son, what is the chance that he is colorblind? _____If they have a daughter, what is the chance she is colorblind?_____ Carrier? __
Questions
Is it possible for a man to be a "carrier"? ______ Why? ______________________________
Questions
Is it possible for a man to be a "carrier"? NO Why? Because men only have ONE X chromosome so they either “normal” or have the disorder.
Questions
Why is it that men are more likely to inherit sex-linked traits like colorblindness and baldness?
Questions
Why is it that men are more likely to inherit sex-linked traits like colorblindness and baldness? AGAIN… Men only have ONE X chromosome, so they either inherit the “normal” allele on their X chromosome, or they inherit the recessive allele for the disorder.
Questions
Which parent do men inherit sex-linked traits from? _________________
Questions
Which parent do men inherit sex-linked traits from?
Their mothers…because they get their Y from their dad.
Hemophilia
Caused by a recessive allele on the X chromosome, Xh
Causes excessive bleeding even after minor injury due to lack of clotting factors in the blood.
Treatment requires injecting clotting factors
