DNA - Photo by Warren Umoh[/caption]
There are quite a few key terms you need to know for this topic. Let's go through them!
Genes and alleles
Genes
A gene is a section of DNA located at a particular site on a DNA molecule.
- They are a sequence of DNA that code for a polypeptide
- This specific site is called its locus (you can remember this by the word location).
- The base sequence of each gene carries the genetic information that determines the sequence of amino acids in a protein.
- Genes can exist in two or more different forms, called alleles.
Alleles
Alleles are the different variations of a gene.
- Diploid organisms have two alleles, this means one on each chromosome.
- This means alleles at a specific locus can be homozygous if they're both on the same type of allele.
- It means they can be heterozygous if both alleles are different.