Bio 205

Question 1

What is Phenylketonuria?

Answer 1

• Disease that caused by a mutation in the gene thats responsible for the production of an enzyme called phenylalanine hydroxoxylase (PAH)
• PAH should convert phenylalanine from food to trysonine, but instead converts it to phenylpyruvic acid (cannot bind to the substrate)
• Buildup leads to mental retardation

Question 2

Haploinsuffiecient

Answer 2

“half is not good enough”

• eg. for mice, gene T encodes for a protein called T-BOX (lets say its needed at a level of 20 arbitrary units)
• for a full length tail, +/+ gives 20
• +/T gives short tail because only 10 arb. units of T-BOX are available(T is dominant here because even though null alleles are usually recessive, for this gene, half is not good enough, so T is dominant)
• T/T will lead to death (T-Box is needed for other bodily functions, not just tail)

Question 3

Haplosufficient

Answer 3

“Half if good enough”

-found when the wildtype wins over the null (heterozygous alleles)

Question 4

Single Gene Inheritance

Answer 4

• When you discover a new phenotype, you want to see if the mutation that’s causing it is found on the same gene
• You also want to see what type of allele you have(if its weak, leaky or null)