Non A T G C base in RefSeq zebrafish mRNA sequence

Question

[xiangwulu]

I found some non A T C G base in refseq zebrafish mRNA sequence: 'Y', 'K', 'R', 'M', 'W'

Couldn't find out what do they mean.

e.g.

NM_001012366.1
http://www.ncbi.nlm.nih.gov/nuccore/59933235?report=fasta
at line:
CCCCCACAGTCCCTGCATTACGGGAATGTGCAGGCAAGAGGAAGCGGTCTCAGGGAGAGGAGGMCGAAGG

This is causing error for some alignment tool, such as bfast.

Thanks

Answer 1

[Lemire]

Could be IUPAC codes for ambiguous nucleotides: http://droog.gs.washington.edu/parc/images/iupac.html

Answer 2

[Juke34]

Yes it is IUPAC. If they crash the tool you use, just mask them (replace them by N)