Date of Award


Document Type


Degree Name

Master of Arts (MA)




Reading disability (RD) is defined as difficulty learning to read and spell despite adequate intelligence and educational opportunity and without demonstratable physical, neurological, or emotional handicap. Investigators have suggested a genetic influence and postulated an autosomal dominant mode of inheritance. The strongest support for this hypothesis came from the observation of linkage between RD and a heteromorphism of the short arm/centromere of chromosome 15. Further analysis indicated the possibility of genetic heterogeneity with some families showing RD due to a gene not on chromosome 15. This research is a report of the results of a linkage analysis of RD verses four genetic markers on chromosome 6. Two are restriction fragment length polymorphisms (D6S8, D6S9) and two are classical red cell and serum markers, Glyoxylase (GLO) and Properdin clotting factor (BF). No linkage between D6S9 and the BF/GLO linkage group was found. Evidence now indicates that D6S9 may not lie on chromosome 6. The distance between BF and GLO was estimated at 10% in the position of D6S8 was determined to be BF-D6S8-GLO or BF-GLO-D6S8. The final analysis assumed order BF-D6S8-GLO. A maximum LOD score of 1.486 was obtained for RD at about 21% from GLO towards the centromere side. This LOD score rose to 2.645 when one family showing linkage with chromosome 15 was omitted. The results suggest that a second gene for RD may lie on chromosome 6.


A Thesis Presented to the Department of Biology and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Master of Arts University of Nebraska at Omaha. Copyright 1989 Yin Yao Shugart.