(Solved) How to figure out probability in genetics

Ange17

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4 years ago

How to figure out probability in genetics

Q1) HbA Normal
HbsHbs- sickle cell
HbA Hbs- heterozygous

A man has the sickle cell trait and his wife is homozygous for the normal allele are planning to have a baby. What is the expected probability of them having a boy with the sickle cell trait? I don't understand probability. First step being the sickle cell trait theres a 50/50 chance the child will inherit it. What is the proability expressed as a percentage So for the last part, do I take the 1/2 x 1/2 = 1/4 (25%) ?
Heres the work I did below:
(HbA Hbs) x (HbA HbA)
1 - HbA HbA
2- HbA Hbs
1- Hbs Hbs

Q2) In chickens, Black allele (B) is dominant over white (b) allele. If the two parents are heterozygous produce two white chicks what is the probability expressed as a percentage?

Q3)What is the probability of the third chick being Black?

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bio_man

wrote...

Educator

4 years ago

Q1.

The probability the baby will have it is 0%. He will be heterozygous, only a carrier. I'm assuming heterozygous means that you're only a carrier of the trait.

Q2.

bb = white

.........B.......b
B.....BB.....Bb
b.....Bb.....bb

1/4 is the percentage of the first offspring being white.

1/4 * 1/4 = 1/16 is the probability that they will have two white chicks. Multiply this by 100% if you want the percentage.

Q3.

Does this assume that the first two were white?
Also, is BB and Bb black? (not sure, they don't say). Let's assume yes

White (1/4)
White (1/4)
Black (3/4)

1/4 * 1/4 * 3/4 = 3/64 or 0.046 or 4.68%

I'm not sure if this is right because of those two questions that are unanswered, ambiguous.

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Ange17 Author

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4 years ago

sorry for Question 1) typo error, what is the probability the couple has a son with the sickle cell trait

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Answer accepted by topic starter

bio_man

wrote...

Educator

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How to figure out probability in genetics

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