Fine mapping of the sex-determining locus in the pedigreed families of fugu.

<p>(A) Genetic map of the sex-determining (SD) region. The frequency of recombinant markers with the sexual phenotype observed in the initial genetic mapping is shown at the top of the linkage map. In the box below, each row is a recombinant individual found in the subsequent screening of 1034 additional siblings and those found in the initial mapping. IDs of males (green boxed) and females (red boxed) are shown in the first column, followed by allele type at markers along the sex chromosome. Alleles shown in red and green are transmitted to nonrecombinant females and males, respectively. Empty blocks indicate that genotypes are non-informative or not assigned. Marker names are indicated at the top of column and their genomic positions are shown above. A combination of markers sca77 and f540 or sca77 and 1189 k is used for screening recombinants from 1034 siblings. The boxed 17.5 kb region shows perfect correlation between the haplotype and phenotypic sex. (B) Schematic diagram of the SD region and gene structures. The positions of SNPs defining the 17.5 kb SD region and two predicted genes in this region are shown. Orange arrows indicate the transcriptional orientation of the genes. Green and red lines indicate the position of genomic DNA clones that were amplified by PCR, cloned into plasmids and sequenced. Two clones each for the genomic regions SD2–14k and SD3–14k were sequenced from X (red line) and Y (green line) chromosomes.