Sunday, 28 September 2008

Facts about genes

As I am the saddest of the three musket-geneticists by far I have decided to post something. I bought a book called ‘a short guide to the Human Genome’. The booked is aimed at people with a background in genetics. Good for lecturers to liven up lectures with facts. The book is a series of questions on various parts of molecular biology and ‘omics’ with short, one page long, answers. These are interesting questions but difficult to find the answers to them without a lot and more importantly, knowing where to look. So here I will look at a few of the more interesting and simple questions.

How many genes are there?
22,740 predicted and known genes. All genes minus predicted transcripts gives us only 18,357.
What is the typical size of a gene?
The median sixe is 16,995 nucleotides.
Which are the largest genes?
CNTNAP2 is 2.3 Mb (remember the genome of E. coli is only 4.63 Mb) and it generates a mRNA of 9.9 Kb. DMD which makes dystrophin is the second largest gene at 2.22 Mb making an mRNA of 14.1 Kb.
Largest proteins?
TTN gene which makes titin, which is 33,423 amino acid residues long. Mucin 16 is the second largest at 14,507 amino acid residues.
How much of the genome is made up of transposable elements?
45%: SINEs 13%, LINEs 21%, LTRs 8% and DDNA transposons 3%.
How many pseudogenes are there?
There are ~5000 pseudogenes with a median size of 1200 nucleotides.
The books seems good but I would suggest you borrow it off me rather than buy a copy.


Catarina Vicente said...

That sounds like a useful book- but does it come with references of where to actually get the official information from? That seems to be the kind of data one likes to write in the introduction of an essay, yet never knowing how to reference...

James Lloyd said...

it depends on the question but he often talks about getting the data off the NCBI website. he also references the 2 genome papers form 2001 and a newer one from 2006.