From micro- to macroevolution: insights from a Neotropical bromeliad with high population genetic structure adapted to rock outcrops

Author(s)

Mota, Mateus Ribeiro ^[1] ; Pinheiro, Fabio ^[2] ; dos Santos Leal, Barbara Simoes ^[2] ; Sardelli, Carla Haisler ^[3] ; Wendt, Tania ^[4] ; Palma-Silva, Clarisse ^{[2, 1]}

Affiliation

^[1] Univ Estadual Paulista, Inst Biociencias, Dept Ecol, BR-13506900 Rio Claro, SP - Brazil

^[2] Univ Estadual Campinas, Inst Biol, Dept Biol Vegetal, BR-13083862 Campinas, SP - Brazil

^[3] Univ Sao Paulo, Inst Biociencias, Dept Genet & Biol Evolut, BR-05508090 Sao Paulo, SP - Brazil

^[4] Univ Fed Rio de Janeiro, Inst Biol, Dept Bot, BR-21941590 Rio De Janeiro, RJ - Brazil

• Document type: Journal article
• Source: HEREDITY; v. 125, n. 5, p. 353-370, NOV 2020.
• Web of Science Citations: 3

Abstract

Geographic isolation and reduced population sizes can lead to local extinction, low efficacy of selection and decreased speciation. However, population differentiation is an essential step of biological diversification. In allopatric speciation, geographically isolated populations differentiate and persist until the evolution of reproductive isolation and ecological divergence completes the speciation process.Pitcairnia flammeaallows us to study the evolutionary consequences of habitat fragmentation on naturally disjoint rock-outcrop species from the Brazilian Atlantic Rainforest (BAF). Our main results showed low-to-moderate genetic diversity within populations, and deep population structuring caused by limited gene flow, low connectivity, genetic drift and inbreeding of long-term isolation and persistence of rock-outcrop populations throughout Quaternary climatic oscillations. Bayesian phylogenetic and model-based clustering analyses found no clear northern and southern phylogeographic structure commonly reported for many BAF organisms. Although we found two main lineages diverging by similar to 2 Mya during the early Pleistocene, species' delimitation analysis assigned most of the populations as independent evolving entities, suggesting an important role of disjoint rock outcrops in promoting high endemism in this rich biome. Lastly, we detected limited gene flow in sympatric populations although some hybridization and introgression were observed, suggesting a continuous speciation process in this species complex. Our data not only inform us about the extensive differentiation and limited gene flow found amongPitcairnia flammeaspecies complex, but they also contain information about the mechanisms that shape the genetic architecture of small and fragmented populations of isolated rock outcrop of recently radiated plants. (AU)

• FAPESP's process: 14/02377-7 - Hybridization among species of Pitcairnia (Bromeliaceae) genus through nuclear microsatellite markers
• Grantee: Juliana Ribeiro Martins Santin
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 14/15588-6 - Phylogeography, population genomics and adaptive variation in Pitcairnia lanuginosa (Bromeliaceae) species complex
• Grantee: Clarisse Palma da Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/07596-0 - Phylogeography, population genomics and speciation of naturally fragmented populations of Bromeliaceae
• Grantee: Clarisse Palma da Silva
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 15/07685-4 - Phylogeography and diversification of lineages of Pitcairnia flammea (Bromeliaceae) complex
• Grantee: Juliana Ribeiro Martins Santin
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 09/52725-3 - Speciation, reproductive isolation, and population genetics in species of Bromeliaceae family: implications for taxonomy, evolution and conservation
• Grantee: Clarisse Palma da Silva
• Support Opportunities: BIOTA-FAPESP Program - Young Investigators Grants