null allele


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Related to null allele: Null mutation

null allele

A segment of DNA which is not known to encode a protein product.

null allele

a form of a gene whose product is either absent at the molecular level, or is present but has no measurable phenotypic function. For example, in a heterozygote with INCOMPLETE DOMINANCE one gene form is a ‘null allele’ and is inactive, while the other allele is unable to compensate for the null allele and so produces an intermediate phenotype.

allele

one of two or more alternative forms of a gene at the same site or locus in each of a pair of chromosomes, which determine alternative characters in inheritance. Called also allelomorph.

blank allele
an allele which produces an antigen which cannot be detected.
null allele
see silent allele (below).
silent allele
one that produces no detectable effect.
References in periodicals archive ?
These 4 disequilibrium loci (BP017, BP301, and AF039660, AF039661) also had the highest estimated null allele frequency among all loci examined ([p.
To determine whether amplification failure caused by mutations in primer-binding regions or by complete deletions of the VNTR region were the reason for these null alleles or the insertion of fragments such as mobile genetic elements resulted in larger (and therefore by capillary electrophoresis) undetectable fragments, the respective fragments were analyzed by using standard gel electrophoresis.
Development of a codominant PCR-based marker for the wheat Wx-B1 null allele.
Although more expensive, sequencing can detect null alleles, is not subject to inference by replacement therapy, and does not require a sample bank of unusual phenotypes.
Tests of Hardy-Weinberg equilibrium for each locus were conducted within each population with GENALEX, and the frequency of null alleles was estimated using the expectation maximization method in FREENA (Chapuis & Estoup 2007) and the maximum likelihood method in ML-NULLFREQ (Kalinowski & Taper 2006).
Besides the SZ and ZZ allele combinations, a combination of other deficient, dysfunctional, or null alleles at the [[alpha].
An additional shortcoming is that phenotyping alone cannot distinguish between an individual who is homozygous for a single allele and an individual who is heterozygous for that allele in trans to a null allele.
Markers were selected based on high polymorphism, low frequency of null alleles, and similar annealing temperatures, as reported by the original designers of each marker (Magoulas et al.
This mutation causes the arginine at position 506 to change to a stop codon, producing a null allele and probably causing a 50% decrease in the measured factor V activity in a heterozygote.
For null allele frequency, our study showed some microsatellite loci frequencies near to 20%.