Down syndrome (DS) or trisomy 21 is the most common genetic disorder with a prevalence of 1 in 660 live births [1]. In 1959, Lejeune and colleagues discovered the genetic basis of DS and named as trisomy of chromosome 21, which is the smallest human autosomal chromo‐ some [2]. Trisomy 21 can occur as three types of chromosomal abnormalities: free trisomy 21, translocation or mosaicism. Free tri...

INTRODUCTION Somatic chromosomal rearrangements that occur in infertile males are thought to be one of the major genetic factors influencing male infertility. The objective of this retrospective study was to evaluate sperm parameters in a group of patients with balanced translocations. MATERIAL AND METHODS We analyzed semen of 84 balanced somatic translocation carriers [35 Robertsonian transl...

Chromosomal abnormalities are thought to be a major contributor to the genetic risks of infertility treatment by intracytoplasmic sperm injection (ICSI). Apart from abnormalities arising de novo, abnormal karyotypes in pregnancies conceived through assisted reproductive technology may be directly derived from predisposing parental aberrations. In a prospective study we have analysed the chromos...

A major obstacle in understanding the etiology of malignant melanoma is the lack of mouse models and transplantable cell lines. We have recently developed a model of primary melanoma in C3H mice induced by ethanol and UV light. The present study characterizes three cell lines, SM190.2, SM190.626, and SD0302, derived from two melanomas produced in the dorsal skin of two C3H mice treated thrice w...

The genus Nothoscordum Kunth comprises approximately 20 species native to South America. Karyologically, the genus is remarkable for its large chromosomes and Robertsonian translocations. Variation in chromosome number has been recorded in a few polyploid species and it is unknown among diploids. This study presents the chromosome number and morphology of 53 individuals of seven populations of ...

Mouse embryos with an additional maternally inherited X chromosome, i.e., disomic for XM (DsXM), cease to grow early in development and have a deficient extraembryonic region. We hypothesized that the underdeveloped extraembryonic region is attributed to two copies of XM that escape inactivation due to maternal imprinting. To examine the validity of this hypothesis and throw more light on the s...

The development of methods to reconstruct phylogenies from karyotypic data has lagged behind what has been achieved with molecular and morphological characters. This hampers our understanding of the role of chromosomal rearrangements in speciation, which depends on knowledge of the karyotypic relationships both among forms that have recently speciated and among forms within species that may spe...

Mouse genetic studies using Robertsonian and reciprocal translocations have shown that certain autosomal regions of loci are subject to a parental germ line imprint, which renders maternal and paternal copies functionally inequivalent in the embryo or later stages of development. Duplication of maternal or paternal copies with corresponding paternal/maternal deficiencies in chromosomally balanc...

Three new karyotypes (2n=40, 44, 52) are described revealing what are probably new cryptic species of Ethiopian spiny mice. Two other diploid numbers have already been reported for the country (2n=36 and 68) and, overall, the five known karyotypic forms constitute a common lineage differentiated by a Robertsonian process. Such arrays of karyotypic forms are known as a 'Robertsonian fan'. This v...

uniparental disomy (upd) is a situation in which both members of a chromosome pair are inherited from one parent. this study has been conducted on a family with a five year-old healthy girl and a mentally retarded boy. the parents were first cousins and they both had robertsonian translocation between their long arm of chromosome 13 and 14 [45, xy t (13q14q)]. their affected son had a similar k...