A study was undertaken to determine the relationship between chromosome composition and embryo development. Bovine cumulus-oocyte complexes were matured in vitro and exposed to semen from one of three different bulls, one of which was a 1/29 Robertsonian translocation carrier. There were no significant differences among the three bulls in their sperm penetration or in the cleavage or developmen...

It has long been known that diploid strains of yeast are more resistant to 7-rays than haploid cells, and that this is in part due to heterozygosity at the mating type (MAT) locus. It is shown here that the genetic control exerted by the MAT genes on DNA repair involves the a1 and a2 genes, in a R M E l independent way. In rad18 diploids, affected in the error-prone repair, the a/a effects are ...

Doubled haploid (DH) technology has been used in breeding programs for several decades and is currently the method of choice in a number of crop species, including barley (Hordeum vulgare L.), rapeseed (Brassica napus L.), maize (Zea mays L.), and wheat (Triticum aestivum L.). In this study we investigated via computer simulation the benefit of using DHs compared with the conventional wheat bre...

ENE action has often been studied by investigating gene dosage relaG tions. This has been done by the addition of chromosome fragments or of entire chromosomes to different genetic backgrounds, exemplified by the work of SCHULTZ (1935) for the gene shaven in Drosophila and of BLAKESLEE (1930) in Datura. STERN and HEIDENTHAL (1944) have shown by their work on position alleles in Drosophila that ...

Anthers of Nicotiana tabacum cultivar Wisconsin 38 were treated with the mutagen ethyl methane sulfonate and cultured to obtain populations of haploid plants of high genetic variability. The selection of these populations by their photosynthetic efficiency was carried out in a hydroponic culture chamber with a CO(2) atmosphere concentration close to the compensation point. Plants that survived ...

The yeast actin cytoskeleton is polarized during most of the cell cycle. Certain environmental factors and mutations are associated with depolarization of the actin cytoskeleton. Is depolarization of the actin cytoskeleton a specific response, or is it a nonspecific reaction to harsh conditions or poor metabolism? If depolarization is a nonspecific response, then any mutation that slows growth ...

The present experiments were undertaken to determine whether, in parthenogenesis, heterozygous embryos develop better than homozygous embryos. Such experiments may provide an approach to elucidating whether fertilized embryos develop better than parthenogenetic ones because of heterozygosity, or if the sperm provides another contribution necessary for complete embryonic development. The parthen...