Lec. 40 Flashcards
Why can genomes change over time? (5)
single base pair changes
transposable elements
tandem duplication
genome duplication
other structural changes
Factors of Genome Diversity
- Genome size (amount of DNA)
- Number of Genes (protein coding)
- Gene Density (genes/million bp)
What are transposable elements (TEs)?
transpons, mobile elements, “jumping” genes
Can DNA be mobile?
YES, almost 1/2 of human DNA is mobile
Is all of your DNA coding?
NO. almost 75% of human DNA is non-coding/repetitive
What is the “Cut & Paste” mechanism
Transposase cuts out transposons and inserts the transposons elsewhere
What is the “Copy & Paste” mechanism
transposons is copied and inserted elsewhere to increase genome size (Retrotransposons)
How are Retrotransposons created?
RNA intermediate is created by the transposon that codes for reverse transcriptase to turn the RNA into DNA to be inserted elsewhere
What are the consequences of transposable elements?
- Exon Shuffling
- Recombination consequences
- Gene Duplication
What is Exon Shuffling
Combination of exons in different sequence leading to a new gene
What is recombination consequences
Crossing over occurs at the wrong point leading to possible extension, deletion, insertions of chromosomes during meiosis I
What is Gene Duplication
gene is duplicated and is able to accumulate new mutations
How do viruses replicate (5 steps)
- attach to host
- enter & transfer DNA/RNA
- make new viral parts
- Self- assemble into new viruses
- exit host
Where do transposable elements come from?
VIRUSES
