What do chromosomes do

Image credit: Genome Research Limited. Cells are the basic building blocks of living things. The human body is composed of trillions of cells, all with their own specialised function.

DNA or deoxyribonucleic acid is a long molecule that contains our unique genetic code. Like a recipe book it holds the instructions for making all the proteins in our bodies. Telomeres are distinctive structures found at the ends of our chromosomes. They consist of the same short DNA sequence repeated over and over again.

Inheritance is the process by which genetic information is passed on from parent to child. Research Advances by Cancer Type. Stories of Discovery. Milestones in Cancer Research and Discovery. Biomedical Citizen Science. Director's Message. Budget Proposal. Stories of Cancer Research. Driving Discovery. Highlighted Scientific Opportunities. Research Grants. Research Funding Opportunities. Cancer Grand Challenges. Research Program Contacts. Funding Strategy.

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Prior Approvals. Annual Reporting and Auditing. Transfer of a Grant. Grant Closeout. Cancer Training at NCI. Resources for Trainees. Funding for Cancer Training. Building a Diverse Workforce. National Cancer Act 50th Anniversary Commemoration. Resources for News Media. Media Contacts. Females have two copies of the X chromosome one inherited from the mother and one from the father.

Males have one copy of the X chromosome inherited from the mother and one copy of the Y chromosome inherited from the father.

Arranged on the chromosomes are genes. Genes are made of DNA and contain the instructions for building proteins and are integral in making and maintaining the human body. Position of the gene on the arm cytogenetic bands. The position is dependent on the light and dark bands that appear on the chromosome when stained and is expressed as a two-digit number one digit represents region and one represents band.

Sometimes the digits are followed by a decimal point and one or more digits. These additional digits represent the distance from the centromere increasing numeric value indicates farther distance from centromere.

Cen — close to the centromere Ter terminus — close to end of either the p or q arms Tel telomere — close to end of either the p or q arms. Example Gene: Anaplastic lymphoma kinase receptor Chromosomal location: 2p23 Location description: chromosome 2, p arm, position Chromosome location, or cytogenetic location, is one way to describe the location of gene on a chromosome.

Another way to identify the location of a gene is by using the molecular location. The sequencing of the base pairs describes the molecular location of the gene on a chromosome. The molecular location is more precise; however, small variations in the address may occur between research groups as a result of varying genome sequencing methods.

A chromosome is a structure that holds your genes. Your genes determine your traits, such as eye color and blood type. Click Image to Enlarge.