3/26/25 Genetic unit test review

What is the correct phenotype ratio when crossing two heterozygous parents in a dihybrid cross?

• 100% heterozygous

• 1:2:1

• 3:1

• 9:3:3:1

Gregor Mendel concluded that traits are...

• not inherited by offspring

• passed from the parents to the offspring

• determined by dominant factors only

• determined by recessive factors only.

_ have an advantage in sex-linked traits due to having 2 X chromosomes

• Males

• Females

In chickens, feather color is codominant.  If a black chicken BB is mated with one that is black and white (BW) what are the chances of having a chicken that is black and white?

• 50%
• 0%
• 25%
• 100%

Best human example is the ABO bloody type.

• polygenic inheritance

• multiple alleles

• sex-linked traits

• linked genes

• incomplete dominance

This is an example of ___________?

• Incomplete dominance
• Co-Dominance

Traits that are often covered up and show only in the homozygous state are called

• homozygous
• heterozygous
• dominant
• recessive

Phenotype is

• what an organism looks like
• letters of the organism
• what the organism does
• found by amniocentesis 

If a father is IA IA and a mother is IA IB, what is the probability for a child with AB blood type?

• 0%

• 25%

• 50%

• 75%

How do recessive, sex-linked disorders differ between males and females

• Females would need 2 lowercase letters to show the disorder while males only need 1

• Males would need 2 lowercase letters to show the disorder while females only need 1

• Both males and females need 2 lowercase letters to show the disorder like regular Mendelian inheritance