Nullisomy

Nullisomy

 

a type of genome mutation in which a pair of chromosomes that are normally present in the genome is missing. Organisms that exhibit nullisomy are called nullisomes. Nullisomy, especially in higher animals, usually results in death. Viable nullisomes can be found among polyploid plants; these nullisomes are used for nullisomic analysis and for establishing new, commercially valuable strains. Nullisomic analysis is used to determine genetic linkage groups and to study the traits that are controlled by these groups. The method is also applied to tissue-culture studies of human nullisomic cells.

References in periodicals archive ?
3, duplications of the lcen region, deletions of the lcen region, breaks in 1q12, breaks between 1q12 and lcen, and numerical aberrations including diploidy/disomy of chromosome 1 and chromosome 1 nullisomy.
lcen deletions and nullisomy were rare and were excluded from further analyses.
l nullisomy 1/33 0,0,18,18 (1)/1,1,18,18 (32) blastomeres (0,0,18,18) Chromosome XY FISH 14 XY 10 (2-8 cells stage embrys) XX 03 (2-8 cells stage embrys) XXY (triploidy state not ruled 01 (5 cells stage embryo) out by ch.
In the absence of the wheat Ph1 pairing gene, either through nullisomy for 5B or the presence of the ph1b gene, increased meiotic associations have been observed between wheat and rye chromosomes but still at a low level (Upadhya and Swaminathan, 1963; Lacadena, 1967; Dhaliwal et al.
Nullisomy (the loss of a chromosome pair) and tetrasomy (the duplication of a chromosome pair) can further alter the number of chromosomes in a polyploid series (Darlington 1973; Stace 1980; Grant 1981).
Thirty somatic chromosomes originate through tetrasomy, while a tetraploid with 56 somatic chromosomes is reduced by nullisomy to 54 somatic chromosomes.
The following categories of sperm aneuploidy were included as dependent variables: disomy X (sperm FISH genotype X-X-21); disomy Y (Y-Y-21); disomy XY (X-Y-21); disomy 21 (X-21-21 or Y-21-21); overall hyperhaploidy involving chromosomes X, Y, and 21 (sum of XY, disomy X, disomy Y, and disomy 21); sex nullisomy (_21); 21 nullisomy (X_ or Y_); overall hypohaploidy involving chromosomes X, Y, and 21 (sum of sex nullisomy and 21 nullisomy); and diploidy.
A moderately increased prevalence of chromosomes X, Y, and 18 sperm aneuploidies was also observed in these workers but nullisomy was not scored (15).