Genetics Test #1

roles of genetic material

replication and inheritance, information storage, expression (through rna transcription), variation → mutation

hershey chase experiment

• proved nucleic acid is genetic material

• phage (protein capsule + DNA) infects bacteira, whatever goes inside is genetic material

• infected e coli w ohage - labeled heavy phosphorous (DNA) or sulfur (protein)

  • phage ghosts removed, new phages produced had 32P, while 32S is unlabeled → DNA went into cell not protein

purines

pure as gold: A, G - 2 rings

pyrimidines

climb the pyramid - C, T - 1 ring

DNA polarity

because of the 5-3 structure and molecular groups (phosphate and OH)

locus

• broadest place in genome, large or small

• including gene(s) or not depending on size

gene

exons and introns, DNA sequence that encodes a product (can be protein or other)

allele

diff versions of a gene - singlue nucleotide polymorphisms

genotype

genetic makeup (alleles) of an organism - hetero or homozygous

single nucleotide polymorphsim

• 2 individual sequences that vary by 1 base

• genes r 99% consistent, 1% variation (new alleles)

PCR

denaturation, annealing, elngation

restriction enzyme

• cut DNA in staggered (sticky ends) or blunt

• recognize small, 4-8bp, palindromes (same 5-3 on opposite ends)

restirction fragmen t length polymorphism (RFLP)

PCR → cut into pieces → figure out size by running gels

compares sequences to see if lengths of fragments are same (same enzyme sites)

need to know locus sequence, and that cut site is variable

microarray (SNP chips)

1. allele specific probe w/ complimentary DNA to known SNP

2. label fragments of the target DNA with fluorescent probe

3. detection system records hybridization signals - heterozygous or homozygous

short tandem repeats (microsattelites)

• short repetitive sequences that accumulate in genomes

• vary at pop level - how many repeats

• kinship by microsattelite lengths

  • IBD or IBS

• SSR genotyping

identity by state

2 DNA have = nucleotide sequencesm not related

identity by descent

= sequence inherited by common ancestor, know it by identifying many loci

SSR genotyping

• design primers to flank microsattelite w/ fluorescent tags

• record length of multiple SSR - identity by descent

• measure length of fragments based pn PCR

• still need to know macrosatellite loci and primer sequence

copy number variants

• large (>1000bp) region is deleted/duplicated - multiple regions

  • can include 1+ genes, rarer and have more effect on phenotype

FISH (fluorescent in situ hybridization)

• can estimate amount of repeats based on band size

quantitative PCR

• same as normal PCR, but add in DNA intecelating fluorescent dye

  • only inserts in couble stranded DNA - > find out how much double stranded DNA

association mapping

• links genetic markers/variation → phenotype

• measure genotypes, phenotype, then p valye of association

• genome wide association study

p value rulw

p = .05/n → keep same false positive rate for # of tests

DNA compaction levels

DNA → wraps around histone proteins (nucleosomes) → chromatin

chromatin → metaphase chromosomes right before division

3 regularities of chromosome compliments

1. nucleus of somatic (non sex) cells have fixed # of choromsome

2. chromosomes are usually in pairs (2 alleles)

3. gametes re usually haploid

homologous chromosomes

fertilization, different alleles (seperate during meiosis I)

sister chromatids

DNA replication (identital before crossing over)

• seperate during mitosis & meiosis II

polyploidy

2+ homologous chrosomsomess per compliment (like 3 sex chromosomes)

why cells divide

growth, wound repair, turnover of worn out cells, reproduction

interphase

g1, 2, g2

g1

growth, synthesize cell division proteins

S

DNA replication - doubles # of chromatids, = # of chromosomes

G2

biochemical preperation for cell division

G2/M checkpoint - DNA is replicated and undamaged4

western blot

• isolate proteins and determine what is present at each stage

1. isolate protein, denature, coat w/ - charge

2. run proteins through gel

3. 3 stain and blot proteins thru primary and secondary antibodies

4. compare protein presence @ different timepoints

immunofluorescense

label protwin in living.cell - use antibodies with fluorescent labels