Search results
Results from the WOW.Com Content Network
The two possible arrangements, cis and trans, of alleles in a double heterozygote are referred to as gametic phases, and phasing is the process of determining which of the two is present in a given individual. When two genes are located on the same chromosome, the chance of a crossover producing recombination between the genes is related to the ...
Allele. An allele[1], or allelomorph, is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. [2] Alleles can differ at a single position through single nucleotide polymorphisms (SNP), [3] but they can also have insertions and deletions of up to several thousand base pairs. [4]
That means that one heterozygous individual can inherit six or eight functioning class-II alleles, three or more from each parent. The role of DQA2 or DQB2 is not verified. The DRB2, DRB6, DRB7, DRB8 and DRB9 are pseudogenes. The set of alleles that is present in each chromosome is called the MHC haplotype. In humans, each HLA allele is named ...
[citation needed] While in this formation, homologous sites on two chromatids can closely pair with one another, and may exchange genetic information. [5] Because there is a small probability of recombination at any location along a chromosome, the frequency of recombination between two locations depends on the distance separating them.
Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes ' non-sister chromatids that results in recombinant chromosomes. It is one of the final phases of genetic recombination, which occurs in the pachytene stage of prophase I of meiosis during a process called ...
If the two alleles of an inherited pair differ (the heterozygous condition), then one determines the organism's appearance and is called the dominant allele; the other has no noticeable effect on the organism's appearance and is called the recessive allele.
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 ...
Compound heterozygosity. In medical genetics, compound heterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state; that is, an organism is a compound heterozygote when it has two recessive alleles for the same gene, but with those two alleles ...