After analysing the distribution of the numbers of sister chromatid exchanges (SCE) in 200 cells from one individual, we found no evidence to reject the hypothesis of a normal distribution (P greater than 0.50). We then compared the mean numbers of SCE per cell in 18 individuals, three males and three females of each of three age groups (0-10, 30-40, and 60-70 years of age) by means of a one-way analysis of variance, and found that there was no significant difference among them at the level of 5%. When these data were analysed by means of a two-way analysis of variance to test separately the effect of sex and age, we found that the number of SCE per cell does not differ significantly between sexes, but differs with age (P Less Than 0.05). People in the age bracket 30-40 years have a higher number of SCE per cell. Age seems to affect both sexes equally.
We report on a computer program that, given the breakpoints and the chromosomes involved in a translocation, generates all the possible imbalanced gametes, calculates their corresponding imbalances, and arranges them in order of increasing imbalance. When compared to current, more cumbersome criteria from the literature, both methods agreed on 196 cases of 199 (greater than 98%). When compared to observed data from families with aneuploid offspring, both our program and the other reported methods yield a rate of accurate prediction of 87%. The use of the program is illustrated in 20 new translocations from our laboratory. The possible influence of crossing over in meiosis I in altering the gamete that is most likely to be passed to aneuploid live births is discussed.
We estimate the incidence of cystic fibrosis in Ireland to be at least 1 case per 1838 live births. We have analysed DNA from 44 Irish CF patients for the presence of deletion 508, using the polymerase chain reaction. The deletion was found in 76% of their chromosomes, and approximately 58% of the patients are homozygous for this deletion. Our results are not significantly different from those found in Canadian or UK patient populations, in which frequencies are higher than those found in Southern European countries.
De Arce MA, Costigan C, Gosden JR, Lawler M, Humphries P. Further evidence consistent with Yqh as an indicator of risk of gonadal blastoma in Y‐bearing mosaic Turner syndrome. Clin Genet 1992:41:28–32.
An 8‐year‐old girl with some features of Turner syndrome and karyotype 45X/46XY had developed a bilateral gonadoblastoma in her rudimentary ovaries. Her normal Y chromosome showed the characteristic distal fluorescence, as seen in her father's. Another mosaic, this time 45X/46XidicY, and also with some Turner features had rudimentary ovaries, but no gonadoblastoma had developed at age 14.
The nature of her idicY, which showed no fluorescent distal Yq and had one of the centromeres inactivated, was confirmed by in situ hybridisation with a Yp‐specific probe. Using primers from a human Yp‐specific sequence, we amplified DNA extracted from paraffin‐embedded ovarian tissue from both cases, and from a normal testicle and a normal ovary as controls. The finding of the expected Y‐derived PCR product in the rudimentary gonads from these mosaic patients indicates the presence of their Y chromosome in both. We discuss the validity of the findings, and the possible role of sequences in or near the fluorescent part of Yq in the origin of gonadoblastoma in Y‐bearing mosaic Turner syndrome.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.