polymorphisms and genetic markers

Question 1

how much do 2 genomes differ

Answer 1

males and females are 98.5% sames but 2 females are 99.9% majority of differences are single base changes (over 10 milliom)

Question 2

Genome organization

Answer 2

Unique sequence (expressed gene, pseudogenes, duplications)

Middle repetitive DNA (rRNA histones, SINES 13%, LINES 21%, retrotransposons 8%)

Highly reptitive (telomeres, centromeres aka satellite DNA)

Question 3

Noncoding RNA (ncRNA)

Answer 3

Functional RNA not coded into protein
play a role in transcription and translation
microRNA: regulate gene expression
siRNA: silence transcription
snRNA: process pre-RNA
piRNA: epigenetic and post translational gene silencing
long ncRNA: transcription translation epigenetics

Question 4

genetic markers

Answer 4

some types of genetic variants serve as genetic markers
Genetic marker: an identifiable physical location on a chromosome whose inheritance can be monitored

distinguishes two copies of a chromosome, allows us to determine which allele of a chromosome is inherited from a parent to a child, used to identify regions of the genome that harbor disease causing mutations (linkage analysis)
Types of genetic markers: RFLP, SNP, STR (microsattelites), CNV

Question 5

RFLP (restriction fragment length polymorphism)

Answer 5

DNA is cut at a particular location with a restriction enzyme, depending on the enzyme, the size of the DNA fragment can differ

Differences can be detected using southern blot or digestion after PCR

RFLPs often the first tools for genetic finger printing, linkage analysis, and paternity testing

Question 6

Short sequence length polymorphisms (microsatellite DNA)

Answer 6

Short repeats of 234 nucleotides, randomly distributed throughout vertebrate genomes, different forms (alleles) of marker microsatellite can easily be differentiated by size

Question 7

Structural variation: copy number variants

Answer 7

Relatively large number of duplication or deletion of specific regions of the genomes

ranges in size from 50 -1 mil
15% of the human genome is affected by CNVs, 12 per individual

Cantu syndrome

Question 8

linakage analysis

Answer 8

associating genetic markers with genetic conditions