HNPCC
Hereditary nonpolyposis colorectal cancer. Autosomal dominantly inherited disease predisposing to colorectal cancer. May be in association with carcinoma of the endometrium, ovary, stomach, small bowel, and pancreas.

Homeobox Gene
A short stretch of nucleotides whose base sequence is virtually identical in all the genes that contain it. Found in many organisms from fruit flies to human beings.
2. A set of genes that are important in developmental patterns. These establish segments in an embryo that may become specific organs or tissue types. In general, "homeotic" genes are genes that control the development of organisms, and "homeogenes" or "homeobox genes" are the subset of homeotic genes that contain "homeoboxes". "Hox" genes are a subset of homeogenes that determine positional cell differentiation and development. Mutations in Hox genes result in the conversion of one body part into another: for example, in the fruit fly Drosophila, a specific Hox mutation results in a leg developing where an antenna would normally be.
Homeostasis (developmental)
A self-regulating process in development, such that the organism grows up to have much the same form independent of the external influences it experiences while growing up.

Homolog
A member of a chromosome pair in diploid organisms or a gene that has the same origin and functions in two or more species.

Homologous Chromosome
Chromosome containing the same linear gene sequences as another, each derived from one parent.
2. Chromosomes that synapse during meiosis. Such chromosomes are identical with regard to their genetic loci and centromere placement.
3. Chromosomes that pair during meiosis; they contain the same linear sequence of genes, presenting each gene in duplicate.

Homologous recombination
Swapping of DNA fragments between paired chromosomes.