We have isolated two alleles of a previously unidentified meiotic recombination gene, mei-217. Genetic analysis of these mutants shows that mei-217 is a typical "precondition" gene. The phenotypes of the mutants are meiosis specific. The strongest allele has <10% of the normal level of crossing over, and the residual events are distributed abnormally. We have used double mutant analysis to posi...

Double-strand breaks (DSB) initiate meiotic recombination in a variety of organisms. Here we present genetic evidence that the mei-P22 gene is required for the induction of DSBs during meiotic prophase in Drosophila females. Strong mei-P22 mutations eliminate meiotic crossing over and suppress the sterility of DSB repair-defective mutants. Interestingly, crossing over in mei-P22 mutants can be ...

Assembly of Caenorhabditis elegans female meiotic spindles requires both MEI-1 and MEI-2 subunits of the microtubule-severing ATPase katanin. Strong loss-of-function mutants assemble apolar intersecting microtubule arrays, whereas weaker mutants assemble bipolar meiotic spindles that are longer than wild type. To determine whether katanin is also required for spindle maintenance, we monitored m...

Methyl iodide (MeI) is a promising alternative to the phased-out fumigant methyl bromide (MeBr); however, there are concerns about its environmental fate following soil fumigation. Laboratory experiments were conducted to investigate the effect of various environmental factors on the rate of MeI degradation in soil. The chemical was added to soil at 48.6 mg kg(-1) and incubated under different ...

Drosophila MEI-9 is the catalytic subunit of a DNA structure-specific endonuclease required for nucleotide excision repair (NER). The enzymatic activity of this endonuclease during NER requires the presence of a second, noncatalytic subunit called ERCC1. In addition to its role in NER, MEI-9 is required for the generation of most meiotic crossovers. To better understand the role of MEI-9 in cro...

Caramel color is added to many widely-consumed beverages as a colorant. Consumers of these beverages can be exposed to 4-methylimidazole (4-MEI), a potential carcinogen formed during its manufacture. California's Proposition 65 law requires that beverages containing 4-MEI concentrations corresponding to exposures that pose excess cancer risks > 1 case per 100,000 exposed persons (29 μg 4-MEI/da...

Objective: To assess, firstly, the validity of the enthesis index published by Mander (Mander enthesis index (MEI)) and, secondly, to investigate whether it is possible to define a new enthesis index that is less time consuming to perform with at least similar or better properties. Methods: Data from the OASIS cohort, an international, longitudinal, observational study on outcome in ankylosing ...

Measured Equation of Invariance(MEI) is a new concept in computational electromagnetics. It has been demonstrated that the MEI technique can be used to terminate the meshes very close to the object boundary and still strictly preserves the sparsity of the FD equations. Therefore, the nal system matrix encountered by MEI is a sparse matrix with size similar to that of integral equation methods. ...

The D. melanogaster mei-41 gene is required for DNA repair, mitotic chromosome stability, and normal levels of meiotic recombination in oocytes. Here we show that the predicted mei-41 protein is similar in sequence to the ATM (ataxia telangiectasia) protein from humans and to the yeast rad3 and Mec1p proteins. There is also extensive functional overlap between mei-41 and ATM. Like ATM-deficient...

We present the cloning and characterization of mei-P26, a novel P-element-induced exchange-defective female meiotic mutant in Drosophila melanogaster. Meiotic exchange in females homozygous for mei-P26(1) is reduced in a polar fashion, such that distal chromosomal regions are the most severely affected. Additional alleles generated by duplication of the P element reveal that mei-P26 is also nec...