Genetics Practice Problems
This article explores various genetic crosses and the resulting genotypic and phenotypic ratios. By examining classic Mendelian genetics scenarios, such as true-breeding pea plants and interbreeding in roan cows, readers will gain insight into how traits are inherited. It also delves into complex inheritance patterns and calculates probabilities from specific crosses, illustrating the principles of Mendelian and non-Mendelian inheritance. With practical examples, this guide serves as a valuable resource for genetics enthusiasts and students alike.
Genetics Practice Problems
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Presentation Transcript
1. What would be the genotypic and phenotypic ratios be for a cross between a true-breeding tall pea plant and a true-breeding short pea plant?
2. What would be the phenotypic ratio be for the following cross:Tt x tt
3. What would be the genotypic and phenotypic ratio for the following cross:Tt x Tt
4. What would be the genotypic and phenotypic ratios for the following cross:TTAA x ttaa
5. What would be the phenotypic ratio for the following cross:TtAa x ttaa
6. What would be the genotypic and phenotypic ratios for the following cross:TtAa x TtAa
7. In cows, roan coat color is caused by having one red allele (R) and one white allele (W). What is the genotypic ratio of the following cross:RR x WW
8. What is the phenotypic and genotypic ratio of the following cross:RW x RW
9. In snapdragons, red flower color (R) is incompletely dominant to white flower color (R’), what is the phenotypic and genotypic ratio for the following cross:RR x R’R’
10. What are the phenotypic and genotypic ratios of the following cross:RR’ x RR’
11. In Guinea Pigs, 2 genes control coat color. One gene controls whether they will be colored (A) or albino (a). The other gene determines if they will be black (B) or brown (b). What type of inheritance pattern is this?
12. What will be the phenotypic ratio of the following crosses: AaBB x Aabb AaBb x AaBb AaBB x aaBb AaBb x aabb
Probabilities Calculate the probabilities of the production of the offspring for each cross
AAbb x aaBB AaBB
AaBbCc x AaBbCc AAbbCc AABBCC AaBbCc aabbcc
In a heterozygote, the phenotype expressed is blended between what the alleles actually code for.
2 genes affect one trait, but one gene controls the expression of the 2nd gene.
How many gametes are produced during oogenesis? What is the scientific name for the gamete?
b+bvg+vg x bbvgvg • Wild Type: 750 • Double Mutant: 764 • Black – Normal: 120 • Grey – Vestigial: 166 • What is the recombination frequency?
Linkage Map • A-B = 23 mu • A-C = 12 mu • B-C = 11 mu
Linkage Map • A-B = 10 • A-C =5 • A-D = 18 • B-C = 15 • B-D = 8 • C-D = 23
