Lecture 3

Question 1

Genes on the Y chromosome

Answer 1

Y chromosome has very few genes.

Mostly comprised of repetitive, heavily packaged heterochromatin.

Question 2

What do we need the human genome for

Answer 2

Its used to find genes and predict open reading frames

1) Find sequences that could potentially be made into proteins
2) Find genes through homology
3) CpG islands to find genes

Question 3

How is the human genome used to find genes and predict ORFs?

Answer 3

1) Finding sequences that could potentially be made into proteins - those that can be translated and dont contain stop codons )ORFs
2) Find genes through homology - computationally search genome for a sequence that is similar to that found in another species

3) CpG islands
finds genes through areas that contain a lot of C G nucleotides

C-G nucleotides are very mutable, if not in a gene they mutate into something else

An area with loads of C Gc shows that this area is being conserved and so must have a function.
Highly conserved areas likely to contain genes that are used and transcribed and translated.

4) RNA sequencing to find genes

harvest RNA of cell -

will be a set of DNA sequence that has been transcribed
so will be enriched for mRNA and likely to be translated into proteins.

Question 4

How many base pairs in the mitochondrial genome?

Answer 4

Just under 17,000 base pairs

Question 5

Mitochondrial eve

Answer 5

follow down the matrilineal line to one woman

the last common ancestor of all our mitochondrial DNA

Question 6

Comparison to closest relatives

Answer 6

Humans and chimps have 40 million differences in their genome out of 3 billion base pairs
35M substitutions
5M indels