tokens: However , when our sample was split into two groups according to the geographic origin of the probands ' grandparents , we were able to confirm the presence of a gene for US1 on chromosome 14q32 ( USH1A ) in 9 families originating from the Poitou region in Western France ( Department of Deux - Sevres ; Zmax = 4.46 at theta = 0 for probe MLJ14 at the D14S13 locus , Morton likelihood ratio test , P < 0.01 ) .