The hybridization and the former steps in the species formation: the study case of Schizochilus Sond

• Grant number: 22/02374-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2022
• End date: July 31, 2024
• Field of knowledge: Biological Sciences - Botany
• Principal Investigator: Ana Paula de Moraes
• Grantee: Samara Evangelista da Silva
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil

Abstract

Hybridisation, often associated with polyploidy, plays a vital role in the evolutionary history of plants. However, in most cases, the identification of hybridisation is based on the detection of individuals with intermediate morphology, which frequently occurs when the hybrid species are already established. In this way, the opportunity to analyse the first steps of the formation of hybrid species is lost. However, it is known that the intermediate morphology does not guarantee the hybrid origin, and such an assessment depends on a multidisciplinary approach with complementary techniques in morphology, ecology and genetics. Following this rationale, in this project, we aim to evaluate the occurrence of hybridisation between two species of African orchids of the genus Schizochilus, S. bulbinella and S. flexuosus. The first detection of individuals with intermediate morphology between these two species was in February 2020, and this population offers us the opportunity to follow the first steps of forming a species in a hybrid zone.Furthermore, the previous analysis of geometric morphometry of the floral parts supported the hybridisation hypothesis. The present proposal aims to expand the study by applying cytogenetic analyses to determine chromosome number, meiotic regularity, pollen viability, and genome size. In this way, we aim to identify whether the hybridisation process is taking place and the observable consequences in the karyotypes and gametes of individuals with intermediate morphology.(AU)