INTRODUCTION TO GENETICS

Inheritance is the study of how characteristics are passed on from parents to their offspring. This is a branch of the science of Genetics

All the information needed to generate a new individual is found in the genes. Each gene codes for a particular feature of that individual (eg. eye colour, skin colour, hair colour, tendency for great height, etc).

Genes are grouped together on bodies found in the nuclei of cells called chromosomes. Chromosomes are made up of the genetic chemical deoxyribonucleic acid (DNA). Each chromosome is composed of two strands (chromatids) joined by a central body called the centromere.

Each body cell contains two sets of chromosomes - one from the mother and one from the father

The karyotype is the full complement of chromosomes in an individual. Most organisms have different numbers of chromosomes

Humans have 22 pairs of non-sex chromosomes (autosomes - 44 in total) and 2 sex chromosomes

In a human male -> 22 pairs of autosomes

an X and a Y sex chromosome

In a human female -> 22 pairs of autosomes

a pair of X chromosomes

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