ABSTRACT
The study provides new data on the stability of gamma radiation-induced chromosome fragments of a putative maternal nuclear genome in an androgenetic vertebrate, rainbow trout (Oncorhynchus mykiss Walbaum). The fragments were found in five of 16 examined individuals and they were mostly centromeric parts of metacentric or subtelocentric chromosomes. Chromosome fragments were identical in all cells of a given androgenetic individual, indicating that segregation of chromosome fragments is active from the early cell divisions. Most of the fragments were telomereless, i.e. they had no telomeric sequences on their ends. This shows that telomeres are not necessary for stability of chromosomal structures in a vertebrate genome. In one individual, the interstitial telomeric sites were found in chromosomes, which could be the effect of joining chromosome fragments.
Subject(s)
Chromosomal Instability/genetics , Chromosomes/genetics , DNA Fragmentation/genetics , Gamma Rays , Oncorhynchus mykiss/genetics , Animals , Centromere/genetics , Indoles , Karyotyping , Parthenogenesis/genetics , Staining and Labeling , Telomere/geneticsABSTRACT
An infant girl was referred for a genetic consultation because of facial appearance suggestive of Wolf-Hirschorn syndrome (WHS), growth retardation and generalized hypotonia. She had an unbalanced karyotype 46,XX,der(4)t(4;9)(p15.2;p22)mat resulting in the deletion of the critical region for WHS and duplication of the critical region for the 9p duplication syndrome. The mother and the grandmother of proposita were the carriers of an apparently balanced translocation 46,XX,t(4;9)(p15.2;p22). The infant's phenotype was characteristic of WHS syndrome rather than that of duplication 9p phenotype. This is probably the first description of WHS phenotype resulting from a familial 4;9 translocation.
