Genome Organisation, Telomeres and Centromeres Flashcards
What is used to examine inter-molecular heterogeneity?
CsCl buoyant density gradients
Why is CsCl buoyant density gradients used?
Allow you to fractionate DNA based on relative GC content rather than charge or size
Where are most genes found?
In GC rich regions
G-band features
Heterochromatic - less transcription
Low GC rich content
Rich in L1 elements
R-band features
Euchromatic - transcriptionally active
High GC content
Rich in Alu elements
C-band features
Highly heterochromatic
Contain long arrays of satellite sequences
How much of the human genome is composed of transposable elements?
~45%
How much of the genome comprises of retrotransposons?
42%
What are the different types of transposons?
DNA based transposable elements
Autonomous retrotransposons
Non-autonomous retrotransposons
How much of the genome comprises of DNA based transposons?
~3%
What to DNA based transposable elements encode?
A transposase - enzyme that is responsible for cutting the element out of the genome and copying somewhere else
What are transposase homologous to?
Integrase genes
Are DNA based transposable elements active?
No
What are the two types of autonomous retrotransposons?
with long terminal repeats and without long terminal repeats
Example of a autonomous retrotransposon with an LTR
HERV (Human Endogenous RetroViruses)
Classes I, II, III
