Question

Soap Opera Genetics - Genetics to Resolve Family Arguments 1. How could our baby be an albino? Tiffany and Joe have just had a baby and are very surprised to learn that their baby is albino with very pale skin and hair color. Tiffany's sister comes in to visit Tiffany and the new baby, and Joe goes out to talk with his sister Vicky. Did Tiffany have an affair? Joe is very angry. He tells Vicky, "I think Tiffany had an affair with Frank! He's the only albino we know. Obviously, Tiffany and I aren't albino, so Frank must be the father." Luckily, Vicky is a biology teacher, so she explains how two parents with normal skin color could have an albino baby. She draws a Punnett Square to illustrate her explanation. 1. Draw a Punnett Square to show how two parents with normal skin color could have an albino baby. Use a for the recessive allele that can result in very pale skin and hair color and A for the dominant allele that results in normal skin and hair color. Joe is still angry and he doesn't understand the Punnett Square, so he demands a better explanation. Luckily, Vicky is a patient person, so she explains again how Joe and Tiffany could have an albino baby, making sure that Joe understands each step in the process. Why aren't more babies albino? By now, Joe has calmed down and he is getting interested. He asks Vicky "If that's how it works, it seems as though a quarter of all babies should be albino. How come there are hardly any albino babies?" 2. What explanation should Vicky give to answer this question? Joe is starting to feel guilty for getting so mad. He says "Geez, I feel like a jerk now. I should have known that Tiffany would never cheat on me." Vicky responds, "That's okay. You were upset. Let's just forget about it." Will Tiffany and Joe's next baby be albino? Two years later, Tiffany is pregnant again, and she and Joe are discussing whether their second baby will be albino. Tiffany thinks the baby probably will be albino, but Joe remembers Vicky's explanation, and he tells Tiffany, "No, our second baby can't be albino because only one out of

Answer 1

Answer

Ans:- Given - Tiffany & Joe have normal skin thair colaus Tiffany gave birth to alkino- baby * Hence Tiffany & Joe must be Heterozygous to trad Here A dominant allele ( normal skis & hair colan) a- recessive allele. (pale slas & hair colour) Let cross them P1 → Aa x F1 1 Punnet square AA AI Aa Genotypic Ratio 1 CAA): 2CA0) : 1 000) Phenotypic Raha :- 3 (Normal skin thais) il Calkino) * Probability of getting albino child ý = 1/4 or 28% & Probability of getting normal skin & hair colour child s.34 = 78%

Why aren't more babies albino ?

Because the trait albino is controlled recessive allele i.e' a ', the trait is only expressed in homozygous condition (aa).When recessive allele is present with dominant allele (heterozygous condition-Aa) then its effect is masked by dominant allele.thud probability of getting albino child becomes rare.

Ans-3)No ,Joe is wrong because both parents are heterozygous (Aa) ,they have one dominant allele and one recessive allele.During gamete formation each allele segregate to each gametes (independent assortment) thus each gametes contain either a or A allele.Since fertilization involves meeting of random gametes.Which maintain probability of getting albino child in future too.

Ans-4) probability of joes second baby to be albino is :- 1/4 or 25%.