Medalian genetics

Question 1

Autosomal

Answer 1

encoded on numeric chromosomes

Question 2

Sex-linked

Answer 2

encoded on the X (or the Y) chromosome, thus conferred together with gender

Question 3

Dominant

Recessive

Answer 3

Dominant - a single mutant allele confers a phenotype

Recessive - both alleles must be affected for the trait to be displayed

Question 4

Allele

Locus

Answer 4

Allele - one of the alternative versions of a gene or DNA sequence at a given locus

Locus - position occupied by a gene on a chromosome

Question 5

homozygote

heterozygote

Answer 5

Homozygote - genotype with identical alleles at a given locus

Heterozygote - genotype with different alleles at a given locus

Question 6

Hemizygous

Answer 6

A single allele for a gene

examples

Imprinting

X inactivation

Question 7

Compound heterozygote

Answer 7

genotype with 2 different mutant recessive alleles at one locus for two genes

Example: Tay-Sachs disease

Question 8

Polymorphism

Answer 8

alternate genotypes present in a population at >1%

• SNP’s

Question 9

Co-dominant

Incomplete dominant

Answer 9

Codominant alleles - are both expressed in heterozygous state

(blood types)

Incomplete dominance - phenotype is a combination of alleles (pink flower)

Question 10

Haploinsufficiency

Answer 10

Haploinsufficiency - when one normal allele is insufficient to compensate for loss-of-function of the other

Marfan syndrome a genetic disorder of human connective tissue (fibrin in Marfan)

Question 11

Degree of relationship (n)

Answer 11

the number of uninterrupted line segments connecting two blood relatives in a pedigree chart.

Question 12

Coefficient of relationship

Answer 12

the proportion of genes two related individuals have in common = (½)n

Question 13

Coefficient of inbreeding (F)

Answer 13

the proportion of loci at which a person is homozygous by descent =½´*coefficient of relationship

Question 14

genomic imprinting

Answer 14

one gene is silenced, one is expressed from maternal and paternal contribution

prader willies

Angels

Question 15

variable expressivity

Answer 15

• pts with the same genotype express different symptoms

Question 16

pleiotropy

Answer 16

phenotypic variability– individuals with the same genotype express a range of phenotypes based on the influence of other genes, and the environment (epigenetic factors)

Question 17

delayed onset

Answer 17

– phenotype of genetic disease is not expressed until late in life (Huntington’s)

Question 18

Heteroplasmic

Answer 18

common in mitochondrial, in which a signle cell can have mitochindriawith several different genomes (multiple mitochondria per cell, each divides independently)

Question 19

Haplotype

Answer 19

a sequence of genes frequenly inherited togeather and are not seperated by crossingover

Example: MHC receptors