The distribution of paralogs along the platyfish karyotype reveals ohnologous chromosomes arising in the teleost genome duplication event. (A) Platyfish chromosome 1 (Xma1) has numerous paralogs that are located on Xma20. (B) Reciprocally, Xma20 has numerous paralogs that map on Xma1. (C) Xma16 has many paralogs that map onto Xma10 and, in the middle of Xma16, paralogs that are mostly on Xma5. (D) Reciprocally, most of Xma10 has paralogs lying on Xma16, but two short stretches of Xma10 have paralogs on Xma22. (E) Xma5 has groups of paralogs on several other chromosomes, including Xma16, Xma14, and Xma22.