A silly question about human genome project and genes

[davince]

Hello, everyone.

I have a silly question about human genetics.

I was a clinical laboratory science undergraduate student, and i haven't take any class of molecular biology or genetics, so i'm afraid i'm going to ask a question that may be silly.

I was watching the show about 100 discoveries over the past century by the discovery channel, and when i watched the genetics part, at the end of it, it was about human genome project.

The head scientist said that human has about 26000 genes.

and i have one question that has bothering me since i watched the documentary.

how to know that human has 26000 genes?

from the little knowledge i gathered from general biology. the genes are a piece of nucleic acids.

how to find out human has 26000 genes?

won't a piece of genes may be a piece of nucleic acids that are from different parts along the DNA sequence of the chromosome?

 

(my native language is not English, so if i made many mistakes in writing my question, i apologize. )

 

 

Thank you all.

[Paralith]

A eukaryotic protein-coding gene will have certain characteristics that will allow you to pick it out from a given stretch of DNA.

 

In front (upstream) of the gene are usually promoter sequences, sequences that interact with proteins that aid in or repress gene expression. The gene begins with a start codon, a specific 3 nucleotide code that marks the beginning of a protein. After being transcribed into mRNA and taken to a ribosome, the start codon tells the ribosome where to start reading and adding amino acids.

 

Within a gene, there may be introns, sequences that, once transcribed into mRNA, are removed before moving on to translation. These introns are usually flanked by predictable sequences, so that the proteins that splice them out can recognize them.

 

Finally, the gene ends with one of three possible stop codons, which in mRNA tells the ribosome to stop adding amino acids and to release the mRNA and the newly formed protein.

 

By looking for these patterns, we can get an estimate of how many protein coding genes there are in the human genome.

 

I hope that helps.

[davince]

Oh..

i see.

thanks alot:)