Abstract Detail

Comparative Genomics/Transcriptomics

Carey, Sarah [1], Bentz, Philip [2], Marks, Rose [3], VanBuren, Robert [3], Mercati, Francesco [4], Sunseri, Francesco [5], Leebens-Mack, Jim [2], Harkess, Alex [1].

Plant sex chromosome "Cytogenetics-By-Sequencing".

Assembling genome references for dioecious species needs special considerations than other monoecious or hermaphroditic species. While the sex chromosomes are homologous chromosomes, they represent two very diverged haplotypes within an assembly, relative to autosomes. The nonrecombining, sex-determining region often contains an increase in repeats, faster rates of molecular evolution, and structural changes like inversions, translocations, and deletions. Because of these dynamic characteristics of the sex chromosome pair, knowing which sex has the heterogametic sex chromosome is critical for their proper assembly. And indeed, references need to include both sex chromosomes in the pair for downstream analyses. But sex chromosomes have historically been one of the most challenging parts of a genome to assemble. Moreover, for most dioecious species, identifying which is the heterogametic sex has either not been done using standard cytological approaches or is impossible because they are homomorphic. Here we develop a method for easily identifying the sex chromosome cytotype in dioecious species by using Illumina sequencing of a few known female and male isolates. We first test this pipeline using species with known sex chromosome systems, and next use it to identify the heterogametic individual in previously unstudied systems. The pipeline is cost-effective and the data can easily be repurposed for examining the sex-determining region and/or patterns of nucleotide diversity after building a pseudomolecule-scale reference of the heterogametic sex.

1 - Auburn University, Department of Crop, Soil, and Environmental Sciences, Auburn, AL, USA
2 - University of Georgia, Department of Plant Biology, Athens, GA, USA
3 - Michigan State University, Department of Horticulture, East Lansing, MI, USA
4 - Institute of Biosciences and Bioresources (IBBR), National Research Council of Italy (CNR), Palermo, Italy
5 - University Mediterranea of Reggio Calabria, Department of Agriculture, Reggio Calabria, Italy

Keywords:
Dioecy
sex chromosomes
methods
Angiosperms.

Presentation Type: Oral Paper
Session: CGT1, Comparative Genomics/Transcriptomics I
Location: /
Date: Tuesday, July 20th, 2021
Time: 10:30 AM(EDT)
Number: CGT1003
Abstract ID:704
Candidate for Awards:None