X-linked traits punnet square help please????

i have a test tomorrow and i need help on this practice problems!





1.Pattern baldness a X linked recessive trait. Pattern baldness means that the individual with the trait will experience hair loss later in life. If a normal woman whose father was bald, married a man with a full head of hair, what is the chance of their son losing hair? What is the chance of their daughter losing hair?





2. Using the information from number 1, a normal woman whose father didn't experience hair loss married a man whose hair was already thinning. What is the chance of their daughter losing hair?If their daughter married a balding man, what are the chances that any of her children will experience hair loss?





Thanks so much!

X-linked traits punnet square help please????
1. Mom is x*X and dad is XY





son will only inherit an X-chromosome from his mum so there is a 50% chance of inheriting the trait and it will be expressed if inherited)





A daughter inherits an X-chromosome from each parent. She has the same 50% chance of inheriting the gene with the trait from her mum BUT she will inherit a "normal" X-chromosome from her dad. Therefore she has a 0% chance of losing her hair due to the genetic condition.





2. Normal means the woman is not losing her hair. There are 2 possible genotypes for her: XX or x*X


(she could have inherited an x-chromosome with the trait from her mom)





The man she marries is x*Y





Their daughter could be x*X or x*x* (depending on which x-chromosome she inherits from her mum)





So the daughter has a zero to 50% chance of losing her hair later in life (it all depends on the genotype of the mom).





If she marries a balding man (x*Y) all of their children will inherit the gene from the dad so once again the chances of losing their hair will depend on which chromosome they inherit from the mother.





The boys will only inherit an x-chromosome from mom so there is a 50% to 100% of hair loss.





The daughters will also inherit a chromosome with the trait from the dad but whether or not it is expressed depends on what they receive from the mom -- so the daughters also have a 50% to 100% chance of inheriting hair loss.
Reply:1. half





2.(a) 0


(b)half





do u know how to use punnet square? if u need some tutor, email me

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