Genetic markers indicate that hybrids of Pseudoplatystoma (Siluriformes, Pimelodidae) are reproducing in natural environments in southeastern Brazil

Author(s)

Freitas-Souza, Diogo ; Nobile, Andre Batista ; do Prado, Fernanda Dotti ; Serrano, erica Alves ; Lima, Felipe Pontieri ; Foresti, Fausto ; Porto-Foresti, Fabio ; Oliveira, Claudio

• Document type: Journal article
• Source: Biological Invasions; v. 24, n. 4, p. 10-pg., 2022-01-16.

Abstract

Due to the constant propagule pressure of invasive species, aquaculture is considered to be one of the principal mechanisms for the introduction of non-native fish species into wild habitats in Brazil. The ongoing expansion of fish farming in many inland areas is linked directly to the increase in the production of hybrids. Over the past decade, several records of the occurrence of hybrids have been obtained from wild environments, and several studies have shown that the introduction of non-native taxa has led to genetic introgression in some native species. In this context, the present study evaluated whether a population containing adult Pseudoplatystoma hybrids, on the Mogi-Guacu River in the Upper Parana Basin, southeastern Brazil, has been able to establish reproductive continuity, given that the genetic introgression recorded in the parent species indicates backcrossing in the local population. Initially, 59 fish eggs and larvae were identified as either Pseudoplatystoma corruscans or Pseudoplatystoma reticulatum based on a barcoding sequence of the Cytochrome c oxidase I gene. Using three diagnostic nuclear markers (the RAG2 and 18S gene, and the Prt36 microsatellite), four eggs and larvae (of the 40 sequenced) were identified as members of the parent species (either P. corruscans or P. reticulatum), whereas the other 36 samples were identified as hybrids. The hybrid genotypes indicate the occurrence of recent crosses between the species in the wild environment due to the presence of first generation (F1) hybrids. The fertility of the F1 hybrids was confirmed by the presence of eggs and larvae identified as advanced hybrids, probably either backcrosses or post-F1 hybrids. Hybridization has advanced at an alarming rate in the P. corruscans populations of the Mogi-Guacu River, with the proportion of hybrid individuals increasing progressively over the years. (AU)

• FAPESP's process: 17/12758-6 - Use of DNA metabarcoding as alternative, resolute and low-cost tool to DNA barcoding in ecological studies
• Grantee: André Batista Nobile
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 15/19025-9 - Identification of priority areas for the conservation of threatened species in the Mogi-Guaçu river using techniques of DNA barcode
• Grantee: André Batista Nobile
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/09204-6 - Biodiversity and Biogeography in marine-estuarine fishes (Teleostei) from Brazil
• Grantee: Claudio de Oliveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/26508-3 - Phylogeny of the hyperdiverse order Characiformes (Teleostei: Ostariophysi) using ultraconserved elements
• Grantee: Claudio de Oliveira
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/20610-1 - Study of the biogeography of the Brazilian coast using data population genetic data of marine catfish of the genera Cathorops and Genidens
• Grantee: Claudio de Oliveira
• Support Opportunities: Regular Research Grants