Resolution of natural groups using iterative assignment tests: an example from two species of Australian native rats...

Area of Science:

• Ecology and evolutionary biology
• Genetics and genomics
• Bioinformatics and computational biology

Background:

• Morphological similarities between sympatric Rattus fuscipes and Rattus leucopus in north Queensland hinder accurate field identification.
• Initial field identifications of these rat species did not align with genetic groupings based on microsatellite markers.

Purpose of the Study:

• To evaluate an iterative genetic assignment process for resolving distinct natural groups, such as species and populations.
• To accurately differentiate and identify Rattus fuscipes and Rattus leucopus using genetic data.

Main Methods:

• Utilized an iterative genetic assignment test with five microsatellite loci exhibiting overlapping allele distributions between species.
• Employed a random distribution of samples into initial groups, with iterative reassignment based on genetic data.
• Incorporated mitochondrial DNA sequencing to confirm species identification for genetically defined groups.

Main Results:

• The iterative assignment process successfully separated all samples into two distinct genetic groups by the 10th iteration.
• Mitochondrial DNA analysis confirmed the genetic groups corresponded to Rattus fuscipes and Rattus leucopus.
• The procedure also resolved intraspecific population structure, separating Rattus leucopus from two distinct sampling sites.

Conclusions:

• The iterative genetic assignment method effectively differentiates natural groups, even without diagnostic markers.
• This approach provides a robust analytical tool for resolving species and population-level genetic structure in various biological studies.
• Accurate species identification of Rattus fuscipes and Rattus leucopus was achieved, resolving previous field identification ambiguities.