Genetics Vocabulary

Adenine: A (nitrogen) base found in both DNA and RNA. Adenine forms a (nitrogen) base pair with Thymine in DNA.

Amino acids: The basic building blocks of proteins. There are 20 different amino acid types. Each protein consists of a different sequence of amino acids linked together according to the genetic information encoded in DNA.

Bases (also called nitrogen bases): The molecular building blocks of both DNA and RNA. In DNA, the bases are adenine, thymine, guanine, and cytosine. In RNA, the bases are adenine, URACIL, guanine, and cytosine.

Base Pairs: The nitrogen bases bond with each other to form the rungs of the DNA double helix. These bonded nitrogen bases are called base pairs. In DNA adenine bonds with thymine and cytosine bonds with guanine. (RNA bonds uracil to adenine)

Cell: the basic unit of life; the smallest basic part of every living thing that can function by itself. It is made of a nucleus surrounded by cytoplasm, organelles (similar to organs in a body) and proteins. Each cell contains the entire genome.

Chromosome: A structure of DNA and protein found in the cell nucleus. Each chromosome contains hundreds or thousands of the genes that form our hereditary blueprint. Humans have 23 pairs of chromosomes (each parent contributes one chromosome in each pair), containing a total of 50,000 to 100,000 genes from each parent.

Clone: A genetic duplicate

Cloning: The process of producing a genetically identical group of cells from a single ancestor.

Cytosine: A (nitrogen) base found in both DNA and RNA. Cytosine forms a (nitrogen) base pair with guanine in DNA.

DNA (deoxyribonucleic acid): The genetic material of living organisms; the substance of heredity. It is a large, double-stranded, helical molecule that contains genetic instructions for growth, development, and replication. The rungs of this double helix are made of base pairs.

DNA Fingerprinting: The use of fragments of DNA to identify the unique genetic makeup of an individual. There are the RFLP method and the PCR method.

Gene: A sequence of DNA that represents a fundamental unit of heredity. Most genes encode proteins, but some code for RNA molecules.

Geneticist: A scientist who studies genes, the basic units of heredity, and their variations.

Genetic Engineering: The technology used to genetically manipulate living cells to produce new chemicals or to perform new functions. For example, some bacteria can be genetically engineered to produce a human protein called insulin which can be used to treat humans with diabetes.

Genetics: The study of genes and heredity, or how characteristics are passed from parents to children.

Genome: The total genetic information of a particular organism. The normal human genome is made up of 3 billion base pairs of DNA.

Guanine: A (nitrogen) base found in both DNA and RNA. Guanine forms a (nitrogen) base pair with Cytosine in DNA.

Heredity: All of the traits passed on to children by parents (plant or animal) or the process of transferring these traits.

Mitochondrial DNA (MtDNA): Inherited soley from the mother; found in the mitochondria which is in the cell body.

Nuclear DNA: Inherited as a combination from both parents; unique to every individual except identical twins; found in the cell nucleus

Nucleus: The center part of the cell. It contains 6 feet of DNA in 23 pairs of chromosomes and is the largest part of the cell. Living things are divided into eukaryotes (whose cells have nuclei) and prokaryotes (whose cells have no nuclei).

PCR (polymerase chain reaction): A process developed in mid-1980's to make a large number of copies of a DNA sequence from very little DNA. It is used in forensics when little DNA is available for testing.

Protein: A molecule composed of amino acids linked together in a particular order specified by a gene's DNA sequence. Proteins perform a wide variety of functions in the cell; these include serving as enzymes, structural components, or signaling molecules.

RFLP (restriction fragment length polymorphism): Considered to be the most accurate DNA test; it takes several weeks to complete, and is becoming more frequently used in forensics cases.

Sex Chromosome: In humans, there are two types of sex chromosomes: X or Y. Females have two X chromosomes and males have an X and a Y.

Somatic Cell: Cells that make up the body of an organism. These cells are not involved in reproduction. Reproductive cells are called "germ cells".

Thymine: A (nitrogen) base found only in DNA. Thymine forms a (nitrogen) base pair with Adenine in DNA.

X Chromosome: One of the chromosomes involved in sex determination. Normal human females have two X chromosomes in each somatic cell, while normal males have one X and one Y chromosome in each somatic cell. X-linked--Refers to any gene found on the X chromosome or traits determined by such genes. Refers also to the specific mode of inheritance of such genes.

X-linked: Refers to any gene found on the X chromosome or traits determined by such genes. Refers also to the specific mode of inheritance of such genes.

Y Chromosome: One of the chromosomes involved in sex determination. Normal human males carry one X chromosome and one Y chromosome in each somatic cell, while normal females have two X chromosomes in each somatic cell.