Name: ______Date: ______Block: ______
C.P. Biology
Genetics Problems II
1. Spotted rabbits crossed with solid-colored rabbits produce all spotted offspring. When the F1 rabbits were crossed they produced 32 spotted and 12 solid-colored offspring. Which trait is dependent upon a dominant gene? ______
How do you know? ______
Perform a punnett square of the P1 generation and the F1 generation to prove the results you just explained. Give both genotype and phenotype ratios.
2. In the above problem, how many of the F2 spotted rabbits would you expect to be homozygous? ______How many of the F2 solid-colored rabbits would you expect to be homozygous? ______Explain your reasoning and use your punnett square work to prove your answer.
3. In sheep, white-colored wool is due to a dominant gene and black to a recessive allele. A white ewe crossed with a white ram produced a black lamb. If the same parents produce another lamb, could it be white? ______If so, what is the % chance of that happening? ______List the genotypes of the ewe, ram, and black lamb. Include a punnett square to prove your data.
Ewe: ______Ram: ______Lamb: ______
4. In dogs, wire hair is a dominant trait while smooth hair is recessive. Two wire haired dogs produce a litter of four wire-haired puppies. To determine if the male dog is pure for wire hair or carries the gene for smooth hair, what should you do? ______What type of female should he be crossed with? ______Use punnett squares to prove your reasoning.
5. In radishes, the shape of the bulb may be long, round, or oval. Crosses between a.) long and oval produced 159 long and 156 oval; crosses between b.) long and round produced 576 oval; crosses betweenc.) oval and round produced 203 oval and 199 round; crosses between d.) oval and oval produced 254 round, 493 oval, and 253 long. What type of inheritance pattern is shown with this experiment? ______
Give the genotypes of each of the parents in crosses a-d.
6. In horses, black is dependent upon a dominant gene (B) and chestnut is the recessive trait (b). Trotting gait (T) is dominant over pacing gate (t). Predict the phenotype ratios if a homozygous black, heterozygous trotter horse is crossed with a heterozygous black, heterozygous trotter horse. Show your results in a punnett square.
Phenotype ratio:
7. How many different kinds of gametes could be produced by a guinea pig with the genotype bbLlRrSs?
8. Predict the results of a cross between a mom with blood type AB and a dad with blood type B heterozygous. Show your results with a punnett square. Can they have a child with type O blood? ______
What type of inheritance pattern is this? ______
9. In humans, normal pigmentation (C) is dominant over albinism (c). A normal man marries an albino woman. Their first child is an albino. What are the genotypes of these three individuals? Dad: ______Mom: ______Child: ______If these parents have more children, what will be the probability that they will have more albino children? ______What is the probability that they will produce a normally-pigmented child? ______Show your results in a punnett square.
10. An albino man marries a normally pigmented woman. They have 9 children who are all normally pigmented. What would you surmise are the genotypes are of the
mom: ______, dad: ______, and children: ______? Explain.
11. In cats, yellow fur is dominant (B) over black fur (b). The heterozygous condition (Bb) results in a tortoise-shell pattern. The genes B and b are sex-linked on the X chromosome. What kinds of offspring would be expected to result from the cross of a black male (XbY) and a yellow female (XBXB)? ______Use a punnett square to prove your results.
12. Using the information in problem 11, perform a cross between a black male and a tortoise-shell female cat. What kinds of offspring, and in what ratios, would you expect to see as a result of this mating? ______*
Prove your results in a punnett square.
13. Referencing information from problems 11 and 12, perform a cross between a yellow male and a tortoise-shell female cat. If the female has a litter of four male kittens, what color would they most likely be? ______*
14. In mice, the following series of multiple alleles is known: Ay results in yellow fur. A_ results in gray fur. aa results in black fur. AyAy is a fatal condition. What kinds of offspring, and in what ratios, will result from the following crosses:
Aya X Aa; Ay a X aa; Ay A X Ay A.
15. In the P generation, a dog homozygous dominant for straight fur (FF) is crossed with a dog homozygous recessive for curly fur (F’F’). The results of the F1 generation were 8 puppies with wavy fur. What type of inheritance pattern does this represent? ______If two dogs with curly fur mate and produce a litter of puppies, what would you expect the phenotype ratios to be? ______
Make a punnett square to support your results.
16. Hemophilia is a sex-linked genetic disorder that affects the body’s ability to clot blood properly. If a man with hemophilia marries a normal female, what are the chances that any of their children will have the disease? ______Will any males be affected? ______Any females? ______Now perform the same cross with the female a carrier. How will the results change?
17. Imagine that there is a dominant gene that protects against sun-burning (T) and a recessive gene that increases intolerance to the sun and causes sun-burning (t). If this trait has a simple inheritance pattern, what is the probability that parents would have sun-intolerant children if they are both heterozygous for the trait? ______What if the inheritance pattern were incomplete dominance with the same parents. How would the results change? ______And what if the traits were sex-linked, where dad is XtY and mom is XTXt? ______Prove your answers using punnett squares.