The amount and form of natural genetic variation for recombination were studied in six lines for which second chromosomes were extracted from a natural population of Drosophila melanogaster. Multiply marked second, X and third chromosomes were used to score recombination. Recombination in the second chromosomes varied in both amount and distribution. These second chromosomes caused variation in...

Crossovers mediate the accurate segregation of homologous chromosomes during meiosis. The widely conserved pch2 gene of Drosophila melanogaster is required for a pachytene checkpoint that delays prophase progression when genes necessary for DSB repair and crossover formation are defective. However, the underlying process that the pachytene checkpoint is monitoring remains unclear. Here we have ...

Double translocation heterozygotes are rare, but need not necessarily pose more of a counselling problem than single reciprocal translocation heterozygotes. Nine cases of double translocation are presented, together with a review of the few reports published to date. An attempt is made to provide simple counselling guidelines in the assessment of the risk of producing a liveborn abnormal child....

A reciprocal translocation between the short arm of chromosome 1 and the long arm of chromosome 3 was observed in a pedigree of three carriers (proband, and his brother and mother). In this study, the three carriers had different clinical manifestations: the proband with infertility, his brother with spousal miscarriages, and his mother with no adverse reproductive history. Cytogenetic analysis...

We study the probability distribution of the distance d = n + chi - kappa - psi between two genomes with n markers distributed on chi chromosomes and with breakpoint graphs containing kappa cycles and psi "good" paths, under the hypothesis of random gene order. We interpret the random order assumption in terms of a stochastic method for constructing the bicolored breakpoint graph. We show that ...

S1 The density of common SNPs in the Phase II HapMap and the assembled human genome S2 Analysis of data quality S2.1 Analysis of amplicon structure to genotyping error S2.2 Analysis of genotype discordance from overlap with Seattle SNPs S2.3 Analysis of genotype discordance from fosmid end sequences S2.4 Analysis of monomorphism/polymorphism discrepancies S2.5 Interchromosomal LD S3. Analysis o...

A brother and sister are reported with developmental delay and facial features suggestive of the Cornelia de Lange syndrome. Cytogenetic analysis showed them to be trisomic for the region 3q25.1-26.2 because of the inheritance of an unbalanced interchromosomal insertion from their father, who was a balanced insertion carrier. The clinical phenotype and cytogenetic analysis (including chromosome...

In this communication, we describe two cases of proximal 2q trisomy (2q11.2--> q21.1) resulting from an interchromosomal insertion. The chromosomal origin of the insertion was confirmed by fluorescence in situ hybridisation. An unbalanced karyotype, 46,XX,der(8) ,ins(8;2) (p21.3; q21.1q11.2), was found in the proband and her mother, who both have mild mental retardation, short stature, dysmorph...