how many poypeptide(s) does the typical humen gene specify?

Answer 1

1

Answer 2

Actually, that's wrong. Each gene can't specify only one polypeptide. One major surprise for the human genome project was the small number of genes- only 30,000-40,000. However, we have somewhere around 100,000 or so different polypeptides produced in the body. The typical gene woudl then have to specify at least two or three different polypeptides.

How can this happen? There's a couple ways. One is something called alternative splicing. In humans and other eurkaryotes, after DNA is transcripted, the RNA molecule is modified slightly before it comes mRNA. This processes splices (cuts chunks out) RNA, and scientists have found that the same pre-mRNA molecule can be spliced in different ways to produced different mRNA molecules, and thus can produce a couple different polypeptides. Also, there are cases where proteins can be modified post-translationally, by modification and post-translation processing or by alternative folding.

Answer 3

one. The entire human genome codes for about 30,000 proteins