Biochem Exam 2.2

Front 1

allele

Back 1

alternative versions of a gene

Front 2

locus

Back 2

a gene's specific location along the length of a chromosome

Front 3

homologues chromosome

Back 3

same length, centromere position, banding pattern, same gene at particular locus (not necessarily same allele)

Front 4

monohybrid

Back 4

heterozygous for one character (eg flower color)

Front 5

dihybrid

Back 5

heterozygous for two characters (eg seed color and shape)

*each pair of alleles segregates independently of other pairs during gamete formation

Front 6

mechanisms for dominant alleles

Back 6

1. haploinsufficiency: one copy not sufficient to support normal function

2. dominant negative: mutant copy interferes with function of normal copy

3. gain of function: mutant copy interferes with physiology via novel mechanism

Front 7

familial hypercholesterolemia (FH)

Back 7

autosomal dominant. elevation of serum cholesterol bound to LDL, leads to cardiovascular disease

Front 8

penetrance

Back 8

probability that a gene will have any phenotypic expression at all

Front 9

expressivity

Back 9

severity of expression of the phyenotype among individuals with the same disease-causing genotype

due to modifier genes and/or environmental factors

Front 10

mosaicism (and types)

Back 10

1. somatic mosaicism

2. germline mosaicism

3. both (combo) somatic and germline mos.

'normal' individual produces >1 affected. factor in cancer.

Front 11

anticipation

Back 11

symptoms of genetic disorder become apparent at an earlier age as it is passed on to next generation

eg. huntington disease (an unstable repeat expansion disease)

Front 12

examples of sex-specific genomic imprinting:

Back 12

angelmans syndrom (maternal deletion)

prader-willi syndrome (paternal deletion)

region of chromosome 15 where mom/dad contribution express genes differently

Front 13

chronic myelogenous leukemia

Back 13

myeloid white blood cell precursor

caused by a reciprocal translocation (9-22)

Front 14

aneuploidy

Back 14

fertilization of gametes in which nondisjunction occured

offspring have abnormal number of a particular chromosome

Front 15

polygenic inheritance

Back 15

additive effect of two or more genes on a single phenotypic character

environment typically plays role

Front 16

norm of reaction

Back 16

phenotypic range associated with a genotype

eg blood type has narrow, white blood count has large norm of rxn (altitude, exercise etc)

Front 17

pleiotropy

Back 17

one gene influences multiple, seemingly unrelated phenotypic traits

Front 18

mutations:

loss of function

dominant neg

gain of function

Back 18

lof: mutations reduce/eliminate function of gene product

dom neg: mutations interfere with function of normal copy of gene

Front 19

3 types of heterogeneity

Back 19

heterogeneity:

allele - same gene, diff phenotype

locus - diff gene, same phenotype (eg complex or a pathway step)

phenotypic - same gene diff phenotype, modifier genes

Front 20

heteroplasmy

Back 20

mutation and differences in mitochondrial DNA

Front 21

Stratification

Back 21

like ethnic groups - lead to homozygous