Genome Structure Flashcards
How big (roughly) is the human genome?
3 gbps
Roughly how many genes does the human genome contain?
20000 genes
Which histones form the nucleosome?
2 each of H2A, H2B, H3 and H4
What does histone 1 do?
Binds linker DNA between nucleosomes
What is a metacentric chromosome?
Where short and long arms are of equal length
What is a submetacentric chromosome?
Long long arm and short short arm
What is an Acrocentric chromosome?
When a chromosome doesnt have a short arm
What is the arm length of a chromosome defined by?
The position of the centromere
What are the different definitions of an exome?
all of the coding sequence or the whole gene sequence
What is a gene?
All the DNA that is transcribed into RNA + all the local control regions that are required to ensure quantitatively appropriate tissue-specific expression of the final protein
How much of the genome is intergenic?
98%
What does the intergenic region contain?
Sequences of no known function
What do gene clusters allow for?
Coordinated gene regulation but may just reflect the evolutionary history
If you have ‘n’ exons, how many introns do you have?
N-1
Can you have a gene with no introns?
Yes
Where are TATA boxes found and what do they do?
Promoter region
Recruit general transcription factors and RNA polymerase
Where are regulatory elements found and what do they do?
Promoter regions
Regulate recruitment of RNA polymerase
What direction can RNA polymerase move in?
5’ to 3’
What are the three types of regulatory regions?
Enhancers, silencers and insulators
What do enhancers do in regulatory regions?
Upregulate gene expression
What does position independant mean?
They can take affect from anywhere (ie in the gene or many kilo bases away)
What type of transcription factors are the enhancers targets for?
Activators
What type of transcription factors are the silencers targets for?
Repressors
What do silencers do in regulatory regions?
Downregulate gene expression
