Lecture 4 Meiosis and Linkage
Monday, 29 July 2013
Lecture 3 continued:
Transposable elements are mobile DNA sequences found in the genome of all organisms,
making up 45% of the human genome. Can be inserted into any position in the genome
including protein coding genes disrupting them and causing mutations.
Can also promote rearrangement of genome due to insertions, deletions, duplications and
Retro-transposons (class 1):
Make an RNA copy which is then reverse transcribed and inserted into the DNA.
Can be with or without long terminal repeats and with a different number/order of genes.
"copy and paste", copied RNA from inserted DA to be reverse transcribed and put into a new
place in the genome.
There are 2 types of retrotransposons, LTRs and non-LTRs. LTR's have long terminal repeats,
make up 8% of the genome and are 100bp-5000bp long. Non-LTR's include SINEs and LINEs.
SINE's - have no reverse transcriptase