Genetic Variation Flashcards
Inborn errors of metabolism are:
rare disorders in which an enzyme is deficient, usually recessive, metabolic block
What is consanguinity?
cousin marriage
Abundant and structural proteins:
dominant or codominant inheritance
What is a mutation and germaine mutation?
a mutation is any change producing a new allele germ line means it can be transmitted to offspring
What is a missense mutation?
produces a single amino acid change
What is a nonsense mutation?
produces a stop codon in mRNA
What is a frame shift mutation?
alter all codons downstream from the site of insertion or deletion
Sickle cell disease:
is a result of a single missense mutation that produces an amino acid substitution in the b-glob in chain
Why has SCA allele persisted?
homozygotes SS no benefit but heterozygotes are carriers and resistant to malaria
What is protein electrophoresis?
makes use of the differences in the electrical charge of the protein which is caused by a single amino acid difference
What is a polymorphism?
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
Electrophoresis mechanism:
separation of changed molecules in an electric field, positively charged ions migrate towards negative electrode and vice versa
Genotype vs Phenotype
Phenotype is what you observe and Genotype is what you interpret
What is a silent allele?
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
What is epistasis?
the action of one gene masks the effects of another making it impossible to tell the genotype of the second gene
What are isoforms?
multiple molecular forms of a protein are often called isoforms
What are isoenzymes?
enzymes that exist in multiple molecular forms
Why do isoforma exist?
multiple gene loci encoding a protein with similar properties, multiple alleles, subunit interaction, 2ndary changes such as post translational modification
How do we know a protein is encoded by multiple genes/ alleles?
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
What is a centiMorgan?
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
What is needed for markers for building maps?
must be polymorphic occur on average 300-500bps
