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I am getting peptides using biomaRt library in R for the gene 'BRCA1'. 27 different aminoacid sequences are returned, and 12 of those have an asterisk (*) in the end, while 15 do not. What does that mean? I know that asterisk is used to indicate stop codon. So, does that mean the peptides without an asterisk do not have a stop codon? Is that possible at all? Are all of those valid peptides or not?
Below is the R code I used:
library(biomaRt); mart = useMart('ensembl', dataset='hsapiens_gene_ensembl'); seq = getSequence(id='BRCA1', type='hgnc_symbol', seqType='peptide', mart = mart);
MDLSALRVEEVQNVINAMQKILECPICLELIKEPVSTKCDHIFCKVLLCCPSWSTVVRS* is an example sequence with an asterisk in the end.
MDLSALRVEEVQNVINAMQKILECPICLELIKEPVSTKCDHIFCKSLQESTRFSQLVEELLKIICAFQLDTGLEYANSYNFAKKENNSPEHLKDEVSI is an example without an asterisk.