Genetics

Question 1

Explain the difference between genotype and phenotype.

Answer 1

Genotype: Sequence of DNA inherited (Pp), Phenotype: Anything produced by the genotype (enzyme, antigen, eye color, hormone levels, etc)

Question 2

Explain the difference between gene, locus, and allele.

Answer 2

Gene: Section of DNA on a chromosome, Locus: Specific location of a gene on a chromosome, Allele: One form of the gene at a locus

Question 3

What does the word antithetical mean?

Answer 3

Antigens that represent different forms of a gene product from the same locus (2 alleles at the same locus are antithetical to one another, an offspring will either inherit one or the other)

Question 4

What is an amorph?

Answer 4

A silent gene where no detectable trait is produced

Example is ‘O’ blood type

Question 5

Explain the difference between heterozygous and homozygous.

Answer 5

Heterozygous: two different alleles, Homozygous: two of the same allele

Question 6

What does codominant mean?

Answer 6

Both alleles are expressed and seen phenotypically

Question 7

Are most blood group systems dominant, recessive, or codominant?

Answer 7

Codominant

Question 8

What is the dosage effect?

Answer 8

Where a stronger reaction is achieved with homozygous expression than with heterozygous expression.

Question 9

What is a Single Nucleotide Polymorphism (SNP)?

Answer 9

A difference in a single DNA nucleotide between two alleles created by a substitution of the nucleotide. It must occur within at least 1% of the population to qualify as a SNP.

Question 10

What is a missense mutation?

Answer 10

A change in a codon that alters the amino acid in a peptide

Question 11

What is a nonsense mutation?

Answer 11

When a mutation causes one of the three possible stop codons to form

Question 12

What is the purpose of the Hardy-Weinberg equation?

Answer 12

Mathematical formula allowing the study of Mendelian inheritance throughout populations. Allows us to calculate the genotype frequency and gene frequency in a population.

Question 13

What are the 2 equations used in Hardy-Weinberg calculations?

Answer 13

p + q = 1 and p2 + 2pq + q2 = 1

Question 14

What is a gene or allele frequency?

Answer 14

How frequently an allele appears in the population

Question 15

What values would you be solving for if you are trying to find the allele frequencies in a population?

Answer 15

p and q

Question 16

What is a genotype frequency?

Answer 16

How often we see each allele combination within the population.

Question 17

What value would represent the homozygous dominant genotype frequency in the Hardy-Weinberg equations?

Answer 17

P^2

Question 18

What value would represent the homozygous recessive genotype frequency in the Hardy-Weinberg equations?

Answer 18

q^2

Question 19

What value would represent the heterozygous genotype frequency in the Hardy-Weinberg equations?

Answer 19

2pq

Question 20

What is a phenotype frequency?

Answer 20

How often we see the phenotype in the population.