Evidence of mitochondrial capture in Australian glass shrimp (Paratya australiensis) in south-eastern Queensland

Abstract

Context: The Australian glass shrimp (Paratya australiensis) has been identified as a cryptic species complex and several lineages occur sympatrically in eastern Australia. In south-eastern Queensland, the predominant lineages are '4' and '6', although the only known area of sympatry in the Conondale Range is the result of a translocation. Aim: Our aim was to determine any evidence of natural sympatry between the two lineages in the Mary River catchment area using polymerase chain reatction-restriction fragment length polymorphism (PCR-RFLP) analysis. Methods: Of six sites sampled, only one site showed sympatry between Lineage 4 and 6, so 39 individuals from this site were sequenced using fragment of the mtDNA COI gene and a neighbour joining tree revealed the existence of two lineages. Results: On the basis of two sets of nuclear markers (allozymes and microsatellites), there was no evidence of two species, because all loci conformed to Hardy-Weinberg expectations and only Lineage 4 alleles were identified. Conclusion: These results led to the inference that the existence of two mtDNA lineages could be due to mitochondrial capture. Implication: The current situation in the Broken Bridge High site could be due to historical interbreeding between the two lineages reflected in the mtDNA data but not evident in the nuclear data.