Repetitive nature of the hetetochromatic region of chr-4 compared to the whole zebrafish genome.

(A) Genome wide distribution (chr-1 to 25 across the top of the figure) of genetic elements enriched in the heterochromatic region of chr-4. Rows listed top to bottom: 5S RNA motif, micro RNAs (miRNAs), four different Ensembl multigene families (ENSFM), small nuclear RNAs (snRNAs), transfer RNAs (tRNAs), Kolobok-1 transposon, and pseudogenes. See Table 2 for specifics on these elements. (B) Within chr-4 (position in Mb listed across the top), enriched elements are found in the hetrochromatic region (green) delineated by the mir-430 cluster (light blue) at the centromeric side and sar-4 (red) near the telomere of the p arm. (C) Schematic of chr-4 with locations of the centromere, heterochromatic region and sar-4. (D) Replication banding of a cell cultured from a female zebrafish showing the late replication of chr-4q (arrows), unique among the 50 zebrafish chromosome arms. (E) Enlargement of the chr-4 pair; note