Genetic Variation

Question 1

Inborn errors of metabolism are:

Answer 1

rare disorders in which an enzyme is deficient, usually recessive, metabolic block

Question 2

What is consanguinity?

Answer 2

cousin marriage

Question 3

Abundant and structural proteins:

Answer 3

dominant or codominant inheritance

Question 4

What is a mutation and germaine mutation?

Answer 4

a mutation is any change producing a new allele germ line means it can be transmitted to offspring

Question 5

What is a missense mutation?

Answer 5

produces a single amino acid change

Question 6

What is a nonsense mutation?

Answer 6

produces a stop codon in mRNA

Question 7

What is a frame shift mutation?

Answer 7

alter all codons downstream from the site of insertion or deletion

Question 8

Sickle cell disease:

Answer 8

is a result of a single missense mutation that produces an amino acid substitution in the b-glob in chain

Question 9

Why has SCA allele persisted?

Answer 9

homozygotes SS no benefit but heterozygotes are carriers and resistant to malaria

Question 10

What is protein electrophoresis?

Answer 10

makes use of the differences in the electrical charge of the protein which is caused by a single amino acid difference

Question 11

What is a polymorphism?

Answer 11

two or more alleles in a population each at frequencies greater than 0.01 (carrier frequency greater than 2%), 25-30% proteins show polymorphism, result of mutations in evolutionary past

Question 12

Electrophoresis mechanism:

Answer 12

separation of changed molecules in an electric field, positively charged ions migrate towards negative electrode and vice versa

Question 13

Genotype vs Phenotype

Answer 13

Phenotype is what you observe and Genotype is what you interpret

Question 14

What is a silent allele?

Answer 14

Silent alleles are ones which code for a functional product and they are usually functionally recessive alleles that lead to enzyme deficiency in inborn errors of metabolism are silent alleles

Question 15

What is epistasis?

Answer 15

the action of one gene masks the effects of another making it impossible to tell the genotype of the second gene

Question 16

What are isoforms?

Answer 16

multiple molecular forms of a protein are often called isoforms

Question 17

What are isoenzymes?

Answer 17

enzymes that exist in multiple molecular forms

Question 18

Why do isoforma exist?

Answer 18

multiple gene loci encoding a protein with similar properties, multiple alleles, subunit interaction, 2ndary changes such as post translational modification

Question 19

How do we know a protein is encoded by multiple genes/ alleles?

Answer 19

if there are diff people we expect to see differences in different people, if there are multiple genes we expect to see the same pattern in everyone but there may be differences in different tissues

Question 20

What is a centiMorgan?

Answer 20

equal to 1% chance that a marker at one genetic locus on a chromosome will be separated from a market at a second locus due to crossing over in a single generation

Question 21

What is needed for markers for building maps?

Answer 21

must be polymorphic occur on average 300-500bps