Contents
How big should a SAM file be?
about 25 Gb
At 2 bits per nucleotide, the SAM file should be about 25 Gb for 100 billion bps, but these files are often 500+ Gb.
What does SAM format look like?
SAM stands for Sequence Alignment/Map format. It is a TAB-delimited text format consisting of a header section, which is optional, and an alignment section. If present, the header must be prior to the alignments. Header lines start with ‘@’, while alignment lines do not.
How is a SAM file generated?
Most often it is generated as a human readable version of its sister BAM format, which stores the same data in a compressed, indexed, binary form. Currently, most SAM format data is output from aligners that read FASTQ files and assign the sequences to a position with respect to a known reference genome.
What is the SAM file in Windows?
Security Account Manager
The Security Account Manager (SAM) is a database that is present on computers running Windows operating systems that stores user accounts and security descriptors for users on the local computer.
What does SAM stand for in sAMAccountName?
Internally, Active Directory (AD) uses several naming schemes for a given object. In the case of a User, two fields are of particular relevance: sAMAccountName (SAM-Account) and userPrincipalName (UPN).
Where does the data in SAM format come from?
Most often it is generated as a human readable version of its sister BAM format, which stores the same data in a compressed, indexed, binary form. Currently, most SAM format data is output from aligners that read FASTQ files and assign the sequences to a position with respect to a known reference genome.
What’s the difference between Sam and sequence alignment?
The Sequence Alignment/Map (SAM) format is a generic nucleotide alignment format that describes the alignment of query sequences or sequencing reads to a reference sequence or assembly. Importantly: It is flexible enough to store all the alignment information generated by various alignment programs;
How are reads assigned to the same reference sequence?
For example, a group of reads in the SAM/BAM file may all be assigned to the same reference sequence. Rather than every alignment containing information about the reference sequence, this information is put in the header, and the alignment “points” to the appropriate reference sequence in the header via the RNAME field.
Is the name of a pair / read unique in Sam?
The name of a pair/read is required to be unique in the SAM file, but one pair/read may appear multiple times in different alignment records, representing multiple or split hits. The maximum string length is 254. 3. If SQ is present in the header, RNAME and MRNM must appear in an SQ header record.