A human cDNA encoding a galactokinase (EC 2.7.1.6) was isolated by complementation of a galactokinase-deficient (gal1-) strain of Saccharomyces cerevisiae. This cDNA encodes a predicted protein of ...458 amino acids with 29% identity to galactokinase of Saccharomyces carlsbergensis. Previous studies have mapped a human galactokinase gene (GK1) to chromosome 17q23-25, closely linked to thymidine kinase. The galactokinase gene that we have isolated (GK2) is located on chromosome 15. The relationship between the disease locus for galactokinase deficiency galactosemia, which is responsible for cataracts in newborns and possibly presenile cataracts in adults, and the two galactokinase loci is unknown.
Twenty twin pairs (9 monozygotic and 11 dizygotic) were examined to test the effect of genetic and environmental factors on the etiology of refractive error, axial length of the eyeball, and total ...astigmatism. The twins pairs were ascertained from the nationwide Finnish Twin Cohort Study (FTCS). The monozygosity was confirmed for nine pairs by a blood group analysis adopted for paternity testing procedures. The mean ages of the monozygotic twin pairs was 69 years and of the dizygotic twin pairs 63 years. Spherical equivalent of refractive error and axial length of the eyeball showed higher intrapair correlations among monozygotic pairs than among dizygotic pairs. This suggests, at least in part, a genetic etiology of these traits. Total astigmatism measured by retinoscopy did not show a significant difference in intrapair correlations between monozygotic and dizygotic twin pairs.
A questionnaire to study defects in far vision in the Finnish Twin Cohort Study was sent to 600 twin pairs of 30 and 31 years of age divided equally by gender and zygosity. An excess in female ...prevalence of defects in far vision was observed (p < 0.001). Validation of the questionnaire method to assess negative spherical equivalent of refraction was performed by asking the twins to send their last prescription for glasses. Accuracy of the questionnaire method to detect a defect in far vision was tested using a subsample of cases where actual refraction obtained from the prescription for glasses was available. This actual refraction value was compared with the individuals answers to the questions of far vision. Of the subjects 5.5% were false negatives and 1.8% of the individuals were false positives. In 152 pairs one or both twins had a defect in far vision. Under a threshold liability model, the proportion of total (phenotypic) variance in liability attributable to additive genetic effects was 0.91 in this twin data, while no evidence for effects due to dominance was found.
Astigmatism in 72 twin pairs Teikari, J M; O'Donnell, J J
Cornea,
1989-December, Letnik:
8, Številka:
4
Journal Article
Recenzirano
The Finnish Twin Cohort Study was used to compile twin pairs in whom one or both members had astigmatism. Seventy-two pairs of twins (42 monozygotic and 30 dizygotic) were found. Refractive error and ...astigmatism information was obtained by asking the twins to send their last prescription for glasses to the authors. The correlations between monozygotic twins for astigmatism were not higher than the correlations between dizygotic twins. The differences in the amounts of astigmatism in monozygotic twins was not statistically significantly different than that in dizygotic twins. This suggests that genetic factors do not contribute to astigmatism, leaving environmental causes as major contributors.
Behind the Curtain Finn, Chester E.; Manno, Bruno V.
The Wilson quarterly (Washington),
12/1996, Letnik:
20, Številka:
1
Journal Article, Magazine Article
The quality of education in the US continues to decline despite the growing number of higher education institutions and increasing cost of education. Such a situation can be partly attributed to the ...unique nature of higher education as an industry. Unlike typical businesses, colleges and universities are not forced to streamline their operations to make funds available for expansion. Consequently, much of the added costs of financing expansions are drawn from tuition fees.
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