A threadlike body found in the cell nucleus that is the structural carrier of hereditary characteristics.  The number of chromosomes is characteristic of each species; in sexually reproducing species, chromosomes generally occur in pairs.  A fertilized egg contains two sets of chromosomes, one set from each parent.  Chromosomes are made of protein and nucleic acid.  They represent the linear arrangement of genes, the units of inheritance.

Further Reading and Resources:

A brief history of Human Cytogenetics (cytogenetics is the study of chromosomes, especially in regards to their structure and behaviour.) You will also need to be registered with Medscape.

A tour of genetic basics, including 'What is a chromosome?'

The purpose of the Cytogenetics Gallery is to give you the opportunity to see what chromosomes look like under the microscope and how abnormalities of chromosomes are identified.

Back