ETEROZYGOUS autosomal translocations have been shown to affect recomHbination in the X chromosome in various ways (HINTON 1965); translocations with long interstitial distances increased recombination in X, those with short interstitial distances decreased recombination in X, and those with intermediate interstitial distances had little or no effect. Other incidental tests of translocation hete...

Negative interference describes a situation where two genetic regions have more double crossovers than would be expected considering the crossover rate of each region. We detected negative crossover interference while attempting to genetically map translocation breakpoints in maize. In an attempt to find precedent examples we determined there was negative interference among previously published...

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....

Very few natural polymorphisms involving interchromosomal reciprocal translocations are known in amphibians even in vertebrates. In this study, thirty three populations, including 471 individuals of the spiny frog Quasipaa boulengeri, were karyotypically examined using Giemsa stain or FISH. Five different karyomorphs were observed. The observed heteromorphism was autosomal but not sex-related, ...

Most simple reciprocal translocation homozygotes and heterozygotes are euploid, and normal in genotype. However, translocation heterozygotes form six types of numerically balanced meiotic products. The cross of a translocation heterozygote with a normal individual can yield normal progeny, translocation heterozygotes, or any of four segmentally aneuploid duplication-deficient types (dp-dfs). Us...

Genic allozyme polymorphism and heterozygosity was studied in a large population of the evening primrose, Oenothera biennis, growing in North Haven, Connecticut. This species is a permanent structural heterozygote for the entire complement of 14 chromosomes, and is thus capable of accumulating and maintaining genic heterozygosity. A total of 11 protein species were examined, and these were judg...

saemia in a British hospital, with emphasis on heterozygote detection. Results are reported of a screening programme for galactosaemia covering a period of 2A years and 6415 births. The gene frequency for galactosaemia estimated from the data of the screening programme was 0-002. This conflicted with the known livebirth incidence of at least 1: 50,000 during this same period. 2 of the 4 galacto...

Analysis of meiotic chromosomes from two human male translocation heterozygotes is reported. One had total sterility after maturation arrest and chain configurations at meiosis, and the second had a abnormal children who were presumed to be genetically unbalanced.