Data from: PCR-based isolation of multigene families: lessons from the avian MHC class IIB

The amount of sequence data available today highly facilitates the access
to genes from many gene families. Primers amplifying the desired genes
over a range of species are readily obtained by aligning conserved gene
regions, and laborious gene isolation procedures can often be replaced by
quicker PCR-based approaches. However, in the case of multigene families,
PCR-based approaches bear the often ignored risk of incomplete isolation
of family members. This problem is most prominent in gene families with
highly variable and thus unpredictable number of gene copies among
species, such as in the major histocompatibility complex (MHC). In the
present study we (i) report new primers for the isolation of the MHC class
IIB (MHCIIB) gene family in birds, and (ii) share our experience with
isolating MHCIIB genes from an unprecedented number of avian species from
all over the avian phylogeny. We report important and usually
underappreciated problems encountered during PCR-based multigene family
isolation, and provide a collection of measures to help significantly
improving the chance of successfully isolating complete multigene families
using PCR-based approaches.