A length of DNA made up of thousands of base pairs that codes for one characteristic is called a gene. Each gene has a unique sequence of base pairs that code for a unique characteristic (trait). Different versions of genes are called alleles ( อัลลีล ). For example: A gene code for straight hair (Allele for straight hair) A gene code for curly hair (Allele for curly hair) G C T A G C T A T A G C T A T A G C T A G C T A G C T A T A G C T A G C T A G C T A

How does this DNA chemical define our characteristics? Every three bases on a DNA sequence is called a triplet ( หนึ่งในแฝด 3 คน ). Each triplet codes for a specific amino acid ( กรดอะมิโน ). The amino acids join together to form a protein ( โปรตีน ). G C T A G C T A T A G C T A T A G C T A ValIleLeu Thousands of base pairs Phe Straight hair gene: Amino acids Protein Straight hair structure

Proteins ( โปรตีน ) have an array of very important functions for living systems. Some example are: Collagen ( คอลลาเจน ) – structural component of connective tissue; Keratin ( เคลาติน ) – structural component of skin, hair, and nails; Insulin ( อินซูลิน ) – regulates carbohydrate and fat metabolism in the body; and Haemoglobin ( ฮีโมโกลบิน ) – protein in red blood cells responsible for carrying oxygen

The unique DNA you have in every cell of your body has unique sequences of base pairs that determine your alleles (versions of a gene). These alleles determine how your proteins will be formed and therefore how your being is structured and how it functions.