Genomic DNA and Nucleic Acids Prework 2 Flashcards Preview

MCM Test 1 > Genomic DNA and Nucleic Acids Prework 2 > Flashcards

Flashcards in Genomic DNA and Nucleic Acids Prework 2 Deck (11):

what percentage of DNA is repeated sequences?



what are the two types of repeats in DNA and how do they differ?

interspersed: repeated at different intervals on the chromosome
tandem: repeated over and over right next to each other


what are the 4 classes of interspersed repeats in the human genome and what % do they make up?

LINEs- 20%
SINEs- 13%
HERVs- 8%
DNA transposon fossils- 3%


what are LINEs?

transposons, move via RNA intermediates
6000 nt long, 850,000 copies


what are SINEs?

inactive, but movement can be facilitated by active transposons
Alu repeats
280 nt long, 1.5 million copies


what phenomenon can long interspersed repeats facilitate?

non-homologous recombination


what are 3 types of tandem repeats?

satellite DNA: 3-5% of DNA in each chromosome
minisatellite DNA
microsatellite DNA


where are satellite DNA sequences located at each chromosome?

centromere; binding sited for proteins involved in centromere structure


what can micro- and minisatellite DNA repeats be used for?

DNA fingerprinting


what are segmental duplications?

regions >1kb with greater than 90% identity, present more than once in the genome
duplications can be on the same or multiple chromosomes
5% of genome


how do segmental duplications contribute to genomic rearrangements?

unequal crossing over in meiosis