Hello Monica,
Thank you for your question about your "RefSeq Genes" search results
in the UCSC Genome Browser.
The sequence "chr6_ssto_hap7" represents a "haplotype" sequence in
the GRCh37/hg19 assembly. These alternative haplotype chromosomes
are additional sequence included as part of the assembly that
represent an alternative sequence to a corresponding region of the
genome. You can read more about these haplotypes on the assembly
description page under the "Chromosome naming scheme" section:
http://genome.ucsc.edu/cgi-bin/hgGateway?db=hg19.
The "RefSeq Genes" track in the UCSC Genome Browser is produced my
mapping RefSeq mRNAs to the genome. If an mRNA matches equally well
to two places in the genome, both matches are kept in the track. In
this case, the SYNGAP1 mRNA matched equally well to both the
reference sequence and this "chr6_ssto_hap7" sequence.
I hope this is helpful. If you have any further questions, please
reply to
gen...@soe.ucsc.edu. All
messages sent to that address are archived on a publicly-accessible
Google Groups forum. If your question includes sensitive data, you
may send it instead to
genom...@soe.ucsc.edu.
Matthew Speir
UCSC Genome Bioinformatics Group