By allowing mutations to accumulate spontaneously in different lines derived from a single female of an obligately parthenogenetic Daphnia, it has become possible to estimate the rate at which new genetic variance for life-history characters arises as well as to identify the average pleiotropic effects of mutant polygenes. The estimated polygenic mutation rates are quite compatible with those a...

Background Cytogenetic study of reproductive wastage is an important aspect in determining the genetic background of early embryogenesis. Approximately 15 to 20% of all pregnancies in humans are terminated as recurrent spontaneous abortions (RSAs). The aim of this study was to detect chromosome abnormalities in couples with RSAs and to compare our results with those reported previously. Materia...

the anopheles stephensi mysorensis originating from kazeroon area south of iran, which had been maintained at the laboratory conditions of at 70% relative humidity for almost 150 generations, were subjected to cytogenetical analyses. the ‘instant’ landmarks in the squash preparations of the salivary gland chromosomes are indicative of cytotaxonomic characteristics of the species. the characteri...

The search for the alleles that matter, the quantitative trait nucleotides (QTNs) that underlie heritable variation within populations and divergence among them, is a popular pursuit. But what is the question to which QTNs are the answer? Although their pursuit is often invoked as a means of addressing the molecular basis of phenotypic evolution or of estimating the roles of evolutionary forces...

BACKGROUND Cleavage stage embryos as well as postimplantation embryos have been studied extensively over the years. However, our knowledge with respect to the chromosomal constitution of human embryos at the blastocyst stage is still rudimentary. METHODS In the present paper, a large series of human blastocysts was examined by means of fluorescent in situ hybridization (FISH). RESULTS It wa...

In this study the nature of chromosomal proteins, his tones and nonhistone in resident alveolar macrophages was investigated in comparison to peritoneal neutrophils and calf thymus proteins. Cells were obtained by lavaging the lung and after purity determination they were subjected to fractional extraction procedures. Proteins were then analysed on SDS polyacrylamide gels and densitometric...

We report here a study of viability inbreeding depression associated with the X chromosome of Drosophila melanogaster. Fifty wild chromosomes from Mt. Sinai, New York, and 90 wild chromosomes from Death Valley, California, were extracted using the marked FM6 balancer chromosome and viabilities measured for homozygous and heterozygous females, and for hemizygous males, relative to FM6 males as a...

background: cytogenetic study of reproductive wastage is an important aspect in determining the genetic background of early embryogenesis. approximately 15 to 20% of all pregnancies in humans are terminated as recurrent spontaneous abortions (rsas). the aim of this study was to detect chromosome abnormalities in couples with rsas and to compare our results with those reported previously. materi...