The Family And Gene Study Of Myopia

Purposes: This thesis is part of the study —'The family study of myopia' , which is aresearch project in Cardiff University,UK, carried out in the British and Irish area. The aim of this project is to find out high myopic gene loci and /or test candidate myopic genes in this study population, through the genetic linkage and association analysis of myopia with different kinds of families containing high myopic patient. This thesis mainly discussed the calculation of the heritability of refractive error, and the feasibility of collecting genomic DNA by mailing mouthwashes for large epidemiological study cohort. Methods: ①Calculation of Heritability of refractive error: A large Irish family was used as random sample. Heritability was calculated by mid-parent-offspring regression, parent-offspring regression and sequential oligogene linear analysis routine (SOLAR) methods respectively. The original refractive data and the data obtained after normality-transformation were calculated separately. Refractive errors obtained from cycloplegic retinoscopy and autorefraction were also compared. ② Collection of genomic DNA from myopic families: Sample genes were extracted from exfoliated buccal cells in the mouthwash sent by mail. Before the cohort study,DNAs extracted from mouthwashes collected at the following four time points were compared in purpose to find the optimal collection time,that were, Time1: immediately after getting up in the morning, Time2:anytime before lunch, Time3: anytime before supper, Time4:before going to bed. DNAs were extracted from mouthwash samples with phenol chloride and measured with spectrophotometry for quantitive testing. Then extracted DNAs were used as templates for the polymerase chain reactions of red opsin, a high molecular gene, for qualitative testing. DNA samples were stored at -80°C for 10 months, and used as templates for PCR of red opsin again. The stored DNA were also used as template for the PCR of a segment of transforming growth factor βinduced factor (TGIF)and the PCR products were cleaned and sent for sequencing test. Results: ① Totally we got 15 pairs data for midparent-offspring regression, 24 pairs of data for parent-offspring regression, the valid data used in SOLAR calculation was 137. Heritabilities from three methods when original refractive data and transformed data were used respectively were as followed: 0.56 and 0.60 for mid-parent—offspring regression (Standard Error: 0.16 and 0.23), 0.14 and 0.28 for parent-offspring regression (Standard Error: 0.11 and 0.17), 0.51 and 0.57 for SOLAR (Standard Error: 0.16 and 0.16).There was no significant result whenage was treated as a covariate. ② There was significant correlation (p<0.05) when the refractive errors from cycloplegic retinoscopy and autorefraction examanations of 49...