Exploring the Impact of Repetitive DNAs on Membracidae (Hemiptera) Karyotype Evolution

• Grant number: 24/01521-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): October 01, 2024
• Effective date (End): September 30, 2026
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Diogo Cavalcanti Cabral de Mello
• Grantee: Pablo Mora Ruiz
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The order Hemiptera, encompassing true bugs, is a vast group constituting the fifthlargestinsect order with nearly 107,000 species. Within Hemiptera, the suborderAuchenorrhyncha, specifically the family Membracidae, is notably diverse andmorphologically varied. Membracids, like other Hemipterans, exhibit holocentricchromosomes which are characterized by the lack of a single, localized centromere.While the presence of holocentric chromosomes has been hypothesized to impact anorganism's propensity for chromosomal rearrangements, the chromosomal evolutionof Membracids remains poorly understood. Holocentric chromosomes are foundacross various clades but remain relatively enigmatic in terms of the genetic featuresand molecular mechanisms governing their fusion and fission. Repetitive DNAelements, crucial components of eukaryotic genomes, are implicated in chromosomalrearrangements. This study leverages the diversity of chromosomal arrangementspresent among Membracidae to systematically analyze repetitive DNA landscapesamong species and their role in large-scale genome reorganization, employingbioinformatic tools like RepeatExplorer2 and TAREAN. The investigation furtheremploys fluorescence in situ hybridization (FISH) to physically map abundant repeats,creating chromosomal markers for karyotypic comparisons and understandingchromosomal diversification. Chromosomally assembled genomes will be analyzed toidentify repeats associated with chromosomal rearrangements. Additionally, mappingof the 18S rDNA gene and telomeric sequences aims to uncover rearrangedchromosomes. Phylogenetic analyses utilizing mitogenomes will place karyotypic andrepetitive DNA data in an evolutionary context. The study also intends to test the"library hypothesis'' that posits that related species have a common set of ancestralsatDNA families (i. e. the saellitome). Consequently, closely related species areexpected to exhibit a higher proportion of shared satDNA families compared to moredistantly related ones. This will be studied at the family level, focusing on holocentricchromosomes and highly rearranged karyotypes. This comprehensive investigationwill contribute to a deeper understanding of the genomic dynamics and evolutionaryprocesses within the Membracidae family.