Fig. 7.
Location of basonuclin 2 exons on mouse, human, and zebrafish bacterial artificial chromosomes (BACs). BACs were identified by a BLASTN search of GenBank by using the basonuclin 2 mouse and human mRNA sequences. BAC accession numbers are in bold type. The first and last nucleotide of each BAC is shown. Some BACs have been inverted to follow the direction of transcription of the basonuclin 2 gene. The nucleotide position of each exon on the mouse BACs is indicated. The corresponding position on the human and zebrafish BACs is also given. Only exons 5 and 6 have each been found in both human and mouse transcripts found in GenBank. Exons 1–4 have only been found in mouse transcripts, but they are likely to exist in the human, because the corresponding sequences of the human BACs are highly conserved and surrounded by consensus splice sites. Exons 5a and 5b have been found in human transcripts only. In contrast to exon 5b, exon 5a is probably specific to the human: the corresponding sequence is poorly conserved on the mouse BAC, where it is not surrounded by obvious splice sites.