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Glossary Term
The X or Y chromosome in human beings that determines the sex of an individual. Females have two X chromosomes in diploid cells; males have an X and a Y chromosome. The sex chromosomes comprise the 23rd chromosome pair in a human karyotype.
Glossary Term
A structure found in cells that is comprised of a strand of linearized double-stranded DNA plus proteins that package the DNA in a condensed coil form and regulate chromosomal function.
Glossary Term
Mutually exclusive alternative forms of the same gene occupying the same locus on homologous chromosomes, differing in nucleotide sequence and governing the same biochemical and developmental process.
Glossary Term
A chromosome not involved in sex determination. The diploid human genome consists of a total of 46 chromosomes which includes 22 pairs of autosomes.
Glossary Term
The nonstaining primary constriction of a chromosome which is the point of attachment of the spindle fiber; provides the mechanism of chromosome movement during cell division; the centromere divides the chromosome into two arms, and its position is constant for a specific chromosome: near one end (acrocentric), near the center (metacentric), or between (submetacentric).
Glossary Term
The genetic material of the nucleus, consisting of deoxyribonucleoprotein, which occurs in two forms during the phase between mitotic divisions: 1) as heterochromatin, seen as condensed, readily stainable clumps; 2) as euchromatin, dispersed lightly staining or nonstaining material. During mitotic division the chromatin condenses into chromosomes.
Glossary Term
The complete genomic content of an organism, and possibly the full DNA sequence of that organism. It is contained in a set of chromosomes in eukaryotes, a single chromosome in bacteria, or a DNA or RNA molecule in viruses.
Glossary Term
A way of denoting the collective genotype of a number of closely linked loci on a chromosome.
Glossary Term
Having two different allelic forms of a gene, one inherited from each parent, on each of the two homologous chromosomes.
Glossary Term
Having two identical allelic forms of a gene, one inherited from each parent, on each of the two homologous chromosomes.
Glossary Term
A variety of simple di-, tri-, tetra-, and pentanucleotide tandem repeats that are dispersed in the euchromatic arms of most chromosomes.
Glossary Term
Any transmissible change in the genetic material of an organism, which can result from radiation, viral infection, transposition, treatment with mutagenic chemicals and errors during DNA replication or meiosis. The effects of mutation range from single base changes to loss or gain of complete chromosomes. As many of the simpler alterations to DNA may be repaired, such changes are only heritable once the change is fixed in the DNA by the process of replication. Mutations may be associated with genetic diversity or with pathologies including cancer.
