Glossary - Genetic (I)

Identical twin

Twins produced by the division of a single zygote; both have identical genotypes.
See also: fraternal twin

Immunotherapy

Using the immune system to treat disease, for example, in the development of vaccines. May also refer to the therapy of diseases caused by the immune system.
See also: cancer

Imprinting

A phenomenon in which the disease phenotype depends on which parent passed on the disease gene. For instance, both Prader-Willi and Angelman syndromes are inherited when the same part of chromosome 15 is missing. When the father's complement of 15 is missing, the child has Prader-Willi, but when the mother's complement of 15 is missing, the child has Angelman syndrome.

In situ hybridization

Use of a DNA or RNA probe to detect the presence of the complementary DNA sequence in cloned bacterial or cultured eukaryotic cells.

In vitro

Studies performed outside a living organism such as in a laboratory.

In vivo

Studies carried out in living organisms.

Independent assortment

During meiosis each of the two copies of a gene is distributed to the germ cells independently of the distribution of other genes.
See also: linkage

Informatics

See: bioinformatics

Informed consent

An individual willingly agrees to participate in an activity after first being advised of the risks and benefits.
See also: privacy

Inherit

In genetics, to receive genetic material from parents through biological processes.

Inherited

See: inherit

Insertion

A chromosome abnormality in which a piece of DNA is incorporated into a gene and thereby disrupts the gene's normal function.
See also: chromosome, DNA, gene, mutation

Insertional mutation

See: insertion

Intellectual property rights

Patents, copyrights, and trademarks.
See also: patent

Interference

One crossover event inhibits the chances of another crossover event. Also known as positive interference. Negative interference increases the chance of a second crossover.
See also: crossing over

Interphase

The period in the cell cycle when DNA is replicated in the nucleus; followed by mitosis.

Intron

DNA sequence that interrupts the protein-coding sequence of a gene; an intron is transcribed into RNA but is cut out of the message before it is translated into protein.
See also: exon

Isoenzyme

An enzyme performing the same function as another enzyme but having a different set of amino acids. The two enzymes may function at different speeds.