Genetics Practice

Which gene is dominant and which is recessive? p M

Tell the genotype (Homozygous dominant or recessive, heterozygous)? BB bB Bb bb sS

Tell the genotype (Homozygous dominant or recessive, heterozygous)? HH kk WW mm

Tell the phenotype. B is for black hair (dominant gene), and b is for blond hair (recessive gene). BB bb Bb bB

Tell the phenotype. G is for green, and g is for yellow. Gg gg GG gG

Tell the phenotype. R is for red, and r is for blue.

Using the letters D and d, write the following genotypes. Homozygous dominant Heterozygous Homozygous recessive

Punnett Square BB x bb (B=blue hair, b=red hair) What is the probability that the offspring will be homozygous recessive?

Punnett Square 2. Aa x Aa (A=long nose, a=short nose) What is the probability that the offspring will have a short nose?

Punnett Square 3. Mm x MM (M= earlobes attached, m= earlobes free) What is the probability that the offspring will be homozygous dominant?

Punnett Square 4. rr x Rr (R= round, r=wrinkled) What is the probability that the offspring will be heterozygous?

Punnett Square 5. Gg x Gg (G= green, g= yellow) What is the probability that the offspring will be yellow? What are two genotypes that could represent a green individual?

Word problems A dog owner breeds a dog with spots and a dog without spots. Knowing the spots are recessive, what is the genotype of the dog with spots.

Word problems 2. Black fur (B) is dominant to white fur (b). If the mother is homozygous recessive and the father is homozygous dominant, what are the genotypes of the parents? What is the probability that the offspring will be heterozygous? What is the probability that the offspring will have black fur?

Word problems 2a. Black fur (B) is dominant to white fur (b). If both parents are heterozygous, what are the genotypes of the parents? Write the ratios for the offspring genotypes.

Word problems 3. In certain feline species, brown fur (B) is dominant to orange fur (b). If you cross 2 cats with orange fur, what is the probability that the offspring will have orange fur?

Word problems 4. In a specific plant species, flat seeds are dominant (F) and round seeds (f) are recessive. What is the probability of heterozygous offspring if Parent 1 is homozygous dominant and Parent 2 is heterozygous? What is the ratio of the offspring’s genotypes?

Word problems 5. Use the Punnett square provided to find the genotype of the missing parent. (Dimples are dominant (D) and no dimples is recessive (d). ? D DD Dd d dd

Word problems 6. In a certain species of pine trees, short needles (N) are dominant to long needles (n). If Parent 1 is homozygous recessive, what would the genotype of Parent 2 need to be in order to have 50% of offspring with long needles.

Word problems 7. In a certain species of plant, the color red (R) is dominant to the color white (r). What would the genotypes of the parents have to be if you wanted a white flower from 2 red parents?