ISSN:
1432-1203
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Linkage data, using the polymorphic markers 52A (DXS51), F9, 4D-8(DXS98), and St14(DXS52), are presented from 14 fragile X pedigrees and from 7 normal pedigrees derived from the collection of the Centre d'Étude du Polymorphisme Humaine. A multipoint linkage analysis indicates that the most probable order of these four loci in normal families is DXS51-F9-DXS98-DXS52. Recombination frequencies ( $$\hat \theta $$ ) corresponding to maximum LOD scores ( $$\hat Z$$ ) were obtained by two-point linkage analysis for a nuber of linkage groups, including: DXS51-F9 ( $$\hat Z$$ =5.94, $$\hat \theta $$ =0.03), F9-DXS98 ( $$\hat Z$$ =0.51, $$\hat \theta $$ =0.26), F9-DXS52 ( $$\hat Z$$ =0.84, $$\hat \theta $$ =0.27), and DXS98-DXS52 ( $$\hat Z$$ =0.32, $$\hat \theta $$ =0.20). A multipoint linkage analysis of these loci, including the fragile X locus, was also performed for the fragile X population and the data support the relative order (DSX51, F9, DXS98)-FRAXA-DXS52. Recombination frequencies and maximum LOD scores, which again were derived from two-point linkage analyses, were obtained for the linkage groups DXS51-F9 ( $$\hat Z$$ =9.96, $$\hat \theta $$ =0) and F9-DXS52 ( $$\hat Z$$ =0.07, $$\hat \theta $$ =0.45), as well as for the groups DXS51-FRAXA ( $$\hat Z$$ =2.42, $$\hat \theta $$ =0.15), F9-FRAXA ( $$\hat Z$$ =1.30, $$\hat \theta $$ =0.18), DXS98-FRAXA ( $$\hat Z$$ =0.05 $$\hat \theta $$ =0.36), and DXS52-FRAXA ( $$\hat Z$$ =2.42 $$\hat \theta $$ =0.15). The linkage data was further tested for the presence of genetic heterogeneity both within and between the fragile X and normal families for the intervals DXS51-F9, F9-DXS52, F9-FRAXA, and DXS52-FRAXA using a modification of the A test. Except for the interval F9-FRAXA (P〈0.10) there was no evidence of genetic heterogeneity for each of the various linkage groups examined. The heterogeneity detected for the interval F9-FRAXA, however, was most likely due to one family (Fx-28) that displayed very tight linkage between these two loci.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00366240
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