Data from: Comparison of 454 pyrosequencing methods for characterizing the major histocompatibility complex of nonmodel species and the advantages of ultra deep coverage
Data files
Jun 26, 2017 version files 184.83 MB
-
List of individuals and MID tags for Gulo gulo MHC DRB exon 2 sequencing reads.csv
2.64 KB
-
README_for_List of individuals and MID tags for Gulo gulo MHC DRB exon 2 sequencing reads.txt
2.25 KB
-
README_for_Reads from run 163 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
README_for_Reads from run 245 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
README_for_Reads from run 329-1 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
README_for_Reads from run 329-2 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
README_for_Reads from run 329-3 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
README_for_Reads from run 329-4 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
README_for_Reads from run Trent-1 of Gulo gulo MHC DRB exon 2 fragment.txt
2.25 KB
-
Reads from run 163 of Gulo gulo MHC DRB exon 2 fragment.fna
23.96 MB
-
Reads from run 245 of Gulo gulo MHC DRB exon 2 fragment.fna
35.34 MB
-
Reads from run 329-1 of Gulo gulo MHC DRB exon 2 fragment.fna
24.97 MB
-
Reads from run 329-2 of Gulo gulo MHC DRB exon 2 fragment.fna
32.85 MB
-
Reads from run 329-3 of Gulo gulo MHC DRB exon 2 fragment.fna
27.81 MB
-
Reads from run 329-4 of Gulo gulo MHC DRB exon 2 fragment.fna
27.97 MB
-
Reads from run Trent-1 of Gulo gulo MHC DRB exon 2 fragment.fna
11.91 MB
Abstract
Characterization and population genetic analysis of multilocus genes, such as those found in the major histocompatibility complex (MHC) is challenging in nonmodel vertebrates. The traditional method of extensive cloning and Sanger sequencing is costly and time-intensive and indirect methods of assessment often underestimate total variation. Here, we explored the suitability of 454 pyrosequencing for characterizing multilocus genes for use in population genetic studies. We compared two sample tagging protocols and two bioinformatic procedures for 454 sequencing through characterization of a 185-bp fragment of MHC DRB exon 2 in wolverines (Gulo gulo) and further compared the results with those from cloning and Sanger sequencing. We found 10 putative DRB alleles in the 88 individuals screened with between two and four alleles per individual, suggesting amplification of a duplicated DRB gene. In addition to the putative alleles, all individuals possessed an easily identifiable pseudogene. In our system, sequence variants with a frequency below 6% in an individual sample were usually artefacts. However, we found that sample preparation and data processing procedures can greatly affect variant frequencies in addition to the complexity of the multilocus system. Therefore, we recommend determining a per-amplicon-variant frequency threshold for each unique system. The extremely deep coverage obtained in our study (approximately 5000×) coupled with the semi-quantitative nature of pyrosequencing enabled us to assign all putative alleles to the two DRB loci, which is generally not possible using traditional methods. Our method of obtaining locus-specific MHC genotypes will enhance population genetic analyses and studies on disease susceptibility in nonmodel wildlife species.