An increase in the distribution of data points indicates the presence of genetic or environmental modifiers. Mapping of the genetic control of the spread of points, the uniformity, allows us to allocate genetic difference in point distribution to adjacent, cis effects or to independently segregating, trans genetic effects. Our genetic architecture-mapping experiment elucidated the "environmenta...

Neurofibromatosis type 1 (NF1) is caused by loss of a negative regulator of Ras oncoproteins. Unknown genetic modifiers have been implicated in NF1's characteristic variability. Drosophila melanogaster dNf1 phenotypes include cognitive deficits and reduced growth, both of which resemble human symptoms. We recently reported results of a screen for dominant modifiers of dNf1 growth. Suppressors i...

HE tumorous head (tu-h) abnormality and genetic mechanism were disTcussed by GARDNER (1948), GARDNER and WOOLF (1949) and NEWBY ( 1949). Penetrance, expressivity and relative viability were investigated by GARDNER and RATTY (1952). The influence of high and low temperatures on the expression was described by GARDNER and WOOLF (1950). Modifiers and alleles of tumorous head genes were found in la...

Although significant progress has been made in our understanding of sickle cell disease (SCD) and in the development of new therapies, many questions are still unanswered, and a cure remains elusive. This is particularly evident in the clinical heterogeneity of the disease. Studies have shown the importance of high hemoglobin F determinants and alpha-thalassemia as modifiers of disease severity...