Extensive levels of polygenic variation can be maintained in a population without creating a severe segregational load. One way to account for this is that the alleles are arranged on a chromosome so that different regions balance each other phenotypically. To test whether this occurs in a natural population, we isolated ten Drosophila melanogaster X chromosomes and mapped regions of polygenic ...

Selection for higher and lower meiotic conversion frequencies was investigated in the fungus Ascobolus immersus. Strains carrying the same known gene conversion control factors, which have major effects on conversion frequencies at their specific target locus, sometimes gave significant differences in conversion frequency. Selection for high or low conversion frequencies at the w1-78 site was p...

N an attempt to extend the use of standard methods of genetic analysis to those I naturally important genes which generally act in combination, posterior crossvein formation in D. melanogaster has been chosen for study. The pioneering work of WADDINGTON (1 953, 195 7) relating crossveinless phenocopy sensitivity to crossvein defects under normal conditions has been extended by BATEMAN (1959), M...

OBJECTIVE Chromosomal aberrations are common causes of multiple anomaly syndromes. Recurrent chromosomal aberrations have been identified by conventional cytogenetic methods used widely as one of the most important clinical diagnostic techniques. MATERIALS AND METHODS In this retrospective study, the incidences of chromosomal aberrations were evaluated in a six year period from 2005 to 2011 i...

(see Tully, 1996). These behavioral geneticists were inThe question of how genes contribute to normal individterested in why individual differences in behavior had ual differences in behavior has captured our imagination evolved and how variation is maintained in natural popufor more than a century. Several fundamental questions lations. Most often, they found that many genes (polycome to mind....

UANTITATIVE geneticists have long been concerned with the nature of the Q genes controlling metric characters. Some years ago a fundamental distinction was made between these “minor” genes and the “majoryy genes affecting qualitative characters (MATHER 1943). Although this distinction was convenient at first, it has broken down in recent years. It now appears likely that minor genes (polygenes)...

The robustness of parametric linkage mapping against model misspecification is considered in experimental breeding designs, with a focus on localization of the gene. By examining the expected LOD across the genome, it is shown that single-gene models are quite robust, even for polygenic traits. However, when the marker map is of low resolution, linked polygenes can give rise to an apparent "gho...

A combination of genetic and epigenetic factors may explain the disproportionate incidence and mortality of prostate cancer among African-American males (AAMs) as compared with Caucasian American males (CAMs). We wished to determine whether primary prostate cancers from AAMs and CAMs harbor different patterns or frequencies of chromosomal alterations. Comparative genomic hybridization (CGH) was...

49,xxxxy is rare chromosomal pattern and these patients have mental retardation, small penis, cryptorchidism and skeletal anomalies. we reported a 10 month-old boy who has hypotonia, microcephaly, hypertelorism, depressed nasal bridge, epicanthic folds and bilateral multiple ear tags, high arched palate, down set ears, micrognathia and congenital heart disease such as patent ductus arteriosus (...

The study of chromosomal inversions distribution within natural Anopheles funestus populations from West Africa revealed high levels of genetic structuring. In Burkina Faso, this was interpreted as evidence for incipient speciation, and two chromosomal forms were described, namely 'Folonzo' and 'Kiribina'. Assignation of field collected specimens to one chromosomal form depends upon application...