Genes - Module 1 Reading / Watching

2. What are Genes?

Genes are the basic unit of inheritance containing the information for physical and biological traits. They contain the information necessary for living cells to survive and reproduce . Genes are regions of the DNA .They are passed from parents to offspring. They code for specific proteins or segments of proteins. Humans have approximately 20,000 protein coding genes . These  20,000 protein coding genes are encoded only 1.5% of the entire human genome. Not all genes code only for proteins , some genes encode information for making an RNA molecule that functions other than directly coding for a protein.

Genes in genome of eukaryotes consist of exons and introns. Exons are the protein coding regions of mRNA. These are the regions that contain information for making a protein whereas other regions of the RNA are non-coding and these regions are called introns

The majority of human genes have two or more possible alleles, which are alternative forms of a gene. Differences in alleles account for the considerable genetic variation among people. In fact, most human genetic variation is the result of differences in individual DNA bases within alleles.