(1) chromatid ;
(2) centromere ;
(3) short shoulder;
(4) long shoulder.
Locus ( lat. Locus - place) in genetics means the location of a particular gene on the genetic or cytological map of the chromosome [1] . The DNA sequence variant in this locus is called the allele . An ordered list of loci for any genome is called a genetic map .
Gene mapping is the definition of a locus for a specific biological trait.
Diploid or polyploid cells that carry the same allele at a locus are called homozygous for that locus, and those that carry different alleles are called heterozygous .
Content
Nomenclature
An example of a locus on the cytological map of the chromosome: "6p21.3".
| Component of the nomenclature | Value |
|---|---|
| 6 | Chromosome number. |
| p | Chromosome shoulder: p (from fr. Petit ) - short; q is long. |
| 21 | Area 2, band 1. |
| .3 | Sub-band 3. |
The bands are visible after the differential staining of the chromosomes and are numbered starting from 1, from centromere to telomere. Sub bands and smaller segments are determined by differential coloration of high-resolution chromosomes.
Similarly denoted and a longer stretch. For example, the gene locus “11q1.4-q2.1” means that the gene is located on the long arm of chromosome 11, in the area between sub-band 4 of band 1 and sub-band of 1 band 2.
The end sections of the chromosome are designated “ptel” and “qtel” (from “ telomere ”).
Notes
- ↑ Biological encyclopedic dictionary / Ch. ed. M. S. Gilyarov. - M .: Owls. encyclopedia, 1986. - 831 p.
See also
- Genetics