Send to

Choose Destination
Am J Med Genet. 2001 May 1;100(3):182-6.

Human twinning is not linked to the region of chromosome 4 syntenic with the sheep twinning gene FecB.

Author information

Genetic Epidemiology Unit, Queensland Institute of Medical Research and Joint Genetics Program, The University of Queensland, Brisbane, Queensland, Australia.


The tendency to dizygotic (DZ) twinning is inherited in both humans and sheep, and a fecundity gene in sheep (FecB) maps to sheep chromosome 6, syntenic with human 4q21-25. Our aim was to see whether a gene predisposing to human DZ twinning mapped to this region. DNA was collected from 169 pairs and 17 sets of 3 sisters (trios) from Australia and New Zealand who had each had spontaneous DZ twins, mostly before the age of 35, and from a replication sample of 111 families (92 affected sister pairs) from The Netherlands. Exclusion mapping was carried out after typing 26 markers on chromosome 4, of which 8 spanned the region likely to contain the human homologue of the sheep FecB gene. We used nonparametric affected sib pair methods for linkage analysis [ASPEX 2.2, Hinds and Risch, 1999]. Complete exclusion of linkage (lod < -2) of a gene conferring a relative risk for sibs as low as 1.5 (lambda(s) > 1.5) was obtained for all but the p terminus region on chromosome 4. Exclusion in the syntenic region was stronger, down to lambda(s) = 1.3. We concluded that if there is a gene influencing DZ twinning on chromosome 4, its effect must be minor.

[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center