Genotypes and Phenotypes in Guinea Pigs

The video tutorial explains how to approach word problems involving DI hybrid crosses, focusing on traits in guinea pigs. It covers identifying key parts of the problem, understanding genotype and phenotype outcomes, and determining the genotypes and phenotypes of parent guinea pigs. The tutorial emphasizes the importance of recognizing dominant and recessive traits, as well as incomplete dominance, to predict offspring characteristics.

What should you do when you encounter a word problem with two traits being tracked?

• Focus only on phenotypes

• Ignore one of the traits

• Use a dihybrid cross

• Use a monohybrid cross

In guinea pigs, which hair type is dominant?

• No hair

• Short hair

• Curly hair

• Long hair

What is the result of a heterozygous genotype for fur color in guinea pigs?

• Spotted fur

• Black fur

• White fur

• Gray fur

What genotype results in short hair for guinea pigs?

• Little L little L

• Big L little l

• Big L Big B

• Big L Big L

Which genotype results in black fur in guinea pigs?

• Big B little b

• Big B Big B

• Little B little B

• Big L Big L

What is the genotype of a male guinea pig that is heterozygous for hair length?

• Big B Big B

• Little L little L

• Big L little l

• Big L Big L

What is the genotype of a female guinea pig that is homozygous dominant for hair length?

• Little L little L

• Big B Big B

• Big L little l

• Big L Big L

What phenotype does a male guinea pig with Big L little l and Big B Big B have?

• Short black fur

• Long gray fur

• Long black fur

• Short white fur

What phenotype does a female guinea pig with Big L Big L and little B little B have?

• Long white fur

• Long black fur

• Short white fur

• Short black fur

What is the first step in solving a word problem involving genetics?

• Ignore the genotypes

• Highlight key parts of the problem

• Determine the phenotypes

• Calculate the offspring ratio