Locus (genetics)

locuslociq armp armgenetic locigene locusshort armgene locigenetic locuslocated
In genetics, a locus (plural loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located.wikipedia
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Gene

genesnumber of genesgene sequence
In genetics, a locus (plural loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located.
Therefore, a broad, modern working definition of a gene is any discrete locus of heritable, genomic sequence which affect an organism's traits by being expressed as a functional product or by regulation of gene expression.

Genetics

geneticgeneticistgenetically
In genetics, a locus (plural loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located.
Diploid organisms with two copies of the same allele of a given gene are called homozygous at that gene locus, while organisms with two different alleles of a given gene are called heterozygous.

Allele

allelesallelicmultiple alleles
Genes may possess multiple variants known as alleles, and an allele may also be said to reside at a particular locus.
An allele (, from German Allel and Greek ἄλλος állos “other”) is a variant form of a given gene, meaning it is one of two or more versions of a known mutation at the same place on a chromosome.

Gene map

mapmapping
The ordered list of loci known for a particular genome is called a gene map.
Genes are designated to a specific location on a chromosome known as the locus and can be used as molecular markers to find the distance between other genes on a chromosome.

Zygosity

homozygousheterozygousHomozygote
Diploid and polyploid cells whose chromosomes have the same allele at a given locus are called homozygous with respect to that locus, while those that have different alleles at a given locus are called heterozygous.
Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system.

Gene mapping

mappingphysical mapgenome map
Gene mapping is the process of determining the specific locus or loci responsible for producing a particular phenotype or biological trait.
Gene mapping describes the methods used to identify the locus of a gene and the distances between genes.

Genetic marker

genetic markersmarkermarkers
In genetics, a locus (plural loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located.
Genetic markers have to be easily identifiable, associated with a specific locus, and highly polymorphic, because homozygotes do not provide any information.

Centromere

acrocentricsubmetacentriccentromeric
The cytogenetic bands are counted from the centromere out toward the telomeres.
Centromeres were first thought to be genetic loci that direct the behavior of chromosomes.

Chromosome

chromosomeschromosomalChromosomal number
In genetics, a locus (plural loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located.

Phenotypic trait

traittraitscharacters
Gene mapping is the process of determining the specific locus or loci responsible for producing a particular phenotype or biological trait.
An important reference point along a chromosome is the centromere; the distance from a gene to the centromere is referred to as the gene's locus or map location.

Null allele

null mutationnull mutantnull alleles
A null allele cannot be distinguished from deletion of the entire locus solely from phenotypic observation.

Chromosomal translocation

translocationtranslocationschromosome translocation
See also the definition of a genetic locus.

Oculocutaneous albinism type I

OCA1Oculocutaneous albinism type 1
For example, the locus of gene OCA1 may be written "11q1.4-q2.1", meaning it is on the long arm of chromosome 11, somewhere in the range from sub-band 4 of region 1 to sub-band 1 of region 2.
The location of OCA1 may be written as "11q1.4-q2.1", meaning it is on chromosome 11, long arm, somewhere in the range of band 1, sub-band 4, and band 2, sub-band 1.

Karyotype

karyotypingkaryogramFN
The cytogenetic bands are counted from the centromere out toward the telomeres.
The critical region for this syndrome is deletion of p15.2 (the locus on the chromosome), which is written as 46,XX,del(5)(p15.2).

Human genome

genomehuman DNAhuman geneticist
Each chromosome carries many genes, with each gene occupying a different position or locus; in humans, the total number of protein-coding genes in a complete haploid set of 23 chromosomes is estimated at 19,000–20,000.

Ploidy

diploidhaploid2n
Diploid and polyploid cells whose chromosomes have the same allele at a given locus are called homozygous with respect to that locus, while those that have different alleles at a given locus are called heterozygous. Each chromosome carries many genes, with each gene occupying a different position or locus; in humans, the total number of protein-coding genes in a complete haploid set of 23 chromosomes is estimated at 19,000–20,000.

Polyploidy

tetraploidpolyploidtriploid
Diploid and polyploid cells whose chromosomes have the same allele at a given locus are called homozygous with respect to that locus, while those that have different alleles at a given locus are called heterozygous.

Genome

genomesgenetic materialgenomic
The ordered list of loci known for a particular genome is called a gene map.

Phenotype

phenotypicphenotypesphenotypically
Gene mapping is the process of determining the specific locus or loci responsible for producing a particular phenotype or biological trait.

Telomere

telomerestelomericAlternative Lengthening of Telomeres
The cytogenetic bands are counted from the centromere out toward the telomeres.

Microscope

microscopesmicroscopicmicroscopically

G banding