Degree of similarity of the alleles in an organism
Homozygous and heterozygousSchematic karyogram of a human, showing a diploid set of all chromosomes, except in case of the sex chromosomes in males (bottom right), where there is an X chromosome and a much smaller Y chromosome, which does not have all the genes that the X chromosome has, making a male hemizygous for those genes.
Further information: Karyotype
Zygosity (the noun, zygote, is from the Greek zygotos "yoked," from zygon "yoke") (/zaɪˈɡɒsɪti/) is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism.
Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. 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. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous.
The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some genes have only one allele because there is low variation, others have only one allele because deviation from that allele can be harmful or fatal. But most genes have two or more alleles. The frequency of different alleles varies throughout the population. Some genes may have alleles with equal distributions. Often, the different variations in the genes do not affect the normal functioning of the organism at all. For some genes, one allele may be common, and another allele may be rare. Sometimes, one allele is a disease-causing variation while another allele is healthy.[citation needed]
In diploid organisms, one allele is inherited from the male parent and one from the female parent. Zygosity is a description of whether those two alleles have identical or different DNA sequences. In some cases the term "zygosity" is used in the context of a single chromosome.[1]
^Carr, Martin; Cotton, Samuel; Rogers, David W; Pomiankowski, Andrew; Smith, Hazel; Fowler, Kevin (2006). "Assigning sex to pre-adult stalk-eyed flies using genital disc morphology and X chromosome zygosity". BMC Developmental Biology. 6 (1). Springer Nature: 29. doi:10.1186/1471-213x-6-29. ISSN 1471-213X. PMC 1524940. PMID 16780578.
female parent. Zygosity is a description of whether those two alleles have identical or different DNA sequences. In some cases the term "zygosity" is used in...
Retrieved 2008-10-18. Taylor, Ally. "Twin Zygosity Test for Dichorionic Diamniotic (Di/Di) Twins! Zygosity Reveal". Retrieved 2018-03-30. Am J Med Genet...
factors, as when polygenic inheritance and/or epigenetics are at work. Zygosity refers to the grade of similarity between the alleles that determine one...
Monochorionic twins are monozygotic (identical) twins that share the same placenta. If the placenta is shared by more than two twins (see multiple birth)...
The former is the determinant factor for the number of gene lineages, zygosity mutations and founding haplotypes present in today's Indigenous American...
also tests for unique microdeletions and is the only test that can detect zygosity and fetal sex in twins. Natera also offers Horizon, a carrier-screening...
http://www.equusite.com/articles/basics/colors/colorsGrullo.shtml Dun Zygosity test from Veterinary Genetics Laboratory, School of Veterinary Medicine...
colors. The mane, tail, head, legs, and primitive markings are not diluted. Zygosity for Dun can be determined with a DNA test. The Dun locus is TBX3 on equine...
effects: In the short term, because incestuous reproduction increases zygosity, deleterious recessive alleles will express themselves more frequently...
it is present in both chromosomes, gg (homozygote). This derives from Zygosity, the degree to which both copies of a chromosome or gene have the same...
traits in pea plants, he explains that the “signification” (now termed zygosity) of an individual for a dominant trait is determined by the expression...
Isogenic may refer to: Zygosity Isogenic human disease models Isogenous (disambiguation) This disambiguation page lists articles associated with the title...
give a diagnosis. Other PCR based assays such as iPLEX can also identify zygosity and frequency of the variant.[citation needed] As there is no cure yet...
is recognised in the standards; their distribution is determined by the zygosity of a single dilution gene. As in other blue poultry such as the Blue Andalusian...
Heterozygote, a diploid organism with differing alleles at a genetic locus; see zygosity Hexaethyl tetraphosphate, in chemistry HET acid, alternate term for Chlorendic...
Americans is the determinant factor for the number of genetic lineages, zygosity mutations, and founding haplotypes present in today's Indigenous American...
births or the genetic relationships of their offspring are based on the zygosity of the pregnancy: Monozygotic – multiple (typically two) fetuses produced...
the dun pattern". ScienceDaily (Press release). December 21, 2015. "Dun Zygosity Test." Veterinary Genetics Lab, University of California, Davis. Web page...
The former is the determinant factor for the number of gene lineages, zygosity mutations, and founding haplotypes present in today's Indigenous peoples...
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