Genetics final vocab

FISH

fluorescence in situ hybridization

laboratory technique used to find and map specific DNA sequences, can see extra or deleted chromosomes and detect cancer/mutations

domain

blocks of conserved structure, function found in number of different proteins

paralog

genes that arise by duplication within species

single nucleotide polymorphism (SNP)

DNA sequence differs between individuals by chance

simple sequence repeat (SSR)

varying number of copies of 2-5 nucleotide repeats

Restriction Fragment Length

genetic analysis identifies variations in DNA sequence by cutting DNA w restriction enzymes and measuring length of fragments

polymorphism (RFLP)

alternative splicing

can generate many different proteins from one gene

pseudogene

inactive copies of genes

gene desert

large intergenic regions of mammalians genomes (> 640 kb) that are devoid of genes

yeast two-hybrid screen

genetic method that can identify interactions, interaction between bait and target brings GAL4 DNA binding and activation domains together, gives transcription of lacZ and produces blue colonies on X-Gal

transposon

any segment of DNA that can move from place to place in the genome, few are beneficial to the host

retrotransposon

replicative mechanism of generating a new copy during transposition (moves as RNA intermediate)

replicative transposition

new copy of DNA produced

DNA transposon

replicative or conservative mechanism to excise and move as DNA to a new location, may or may not generate a new transposable element

conservative transposition

No new copy of DNA produced

model organism

experimentally tractable organism

-short generation time

-large # offspring

-easy, inexpensive

-small size

-easy storage

-carry out process of interest

-simple

environmental mutagen

risk of cancer, such as UV light and cigarette smoke

oncogene

gene associate with cancer, mutations are often dominated and activate gene or protein

proto-oncogene

gene that can mutate to be oncogene, function to promote cell growth

tumor suppressor

a gene whose product tends to protect cells from becoming cancerous, recessive

metastasis

migration of cells to new sites, risk of cancer

cyclin

proteins whose level changes through cycle

CDK

cyclin dependent kinase, to target proteins and regulate cell cycle

checkpoint

cell determines if ready for next step

-if S complete, is DNA ok? —> if yes, cell proceeds to M, if no cell arrests until prob fixed

apoptosis

programmed cell death

-excess cells produced are destined to die

-cells that may become cancerous can be killed

caspase

family of proteases (enzymes) that degrade proteins and kill cell

loss of heterozygosity

in atleast one cell, wild type gene lost, often via chromosome loss or deletion

familial adenomatous polyposis coli

mutation in APC; protein degrades cytoplasmic B-catenin

Li-Fraumeni syndrome

mutation in p53 gene, many types of cancer, can’t institute DNA damage check point and can’t induce apoptosis if damage not repaired

sex determination

how sex chromosomes determine sex

sry

sex is determined by the sry gene on the Y chromsome

dosage compensation

normalization of expression of X-linked genes between male and female

morphogen

induce fate depending on concentration (anterior-posterior body axis-concentration gradient of key transcription factors that act as morphogens)

gap genes

divide embryos into distinct domains, regulate pair-rule gene expression

pair rule genes

specify alternative segments, further subdivide embryo into segments

segment polarity genes

regulate A-P identity of cells in each segment

homeotic genes

provide regional identity, more common in mammals

homeosis

replacement of one body part with another

equivalence group

formed from the 6 cells that have the potential to adopt any of 3 fates

population

group of organisms of same species living in same area within which likely to find mates

subpopulation

distinct breeding group within limited area

gene pool

complete set of genetic info within indivdiuals in a population

Hardy-Weinberg

applies to random mating, allele frequencies same in male and female, no selection, no migration, no new mutation, large enough population, equivalent to random union of gametes (p+q=1 and p²+2pq+q²=1)

mating system

norms by which members of population choose mates

assortative mating (positive or negative)

mate choice on basis of some trait

positive: similar phenotypes tend to pair

negative: dif phenotypes tend to pair

inbreeding

multifactorial traits

many traits result from interactions between many alleles and the environment (height, schizophrenia, autism)

quantitative traits

tend to form a bell curve and can be measured rather than perceived

variance

measure of variation

total variance

both genetic and environmental factors

heritability

estimate of the genetic contribution to a trait

linkage equilibrium

occurrence of a specific combination of alleles in cis at two or more loci at a frequency equal to the frequency of the respective allele in the population