Abstract Detail

Functional Genetics/Genomics

MacNeill, Bryan [1], Esque, Todd [2], Defalco, Lesley [3], Flatz, Ramona [4], Smith, Christopher [5], Heyduk, Karolina [6], Yoder, Jeremy [7], McKain, Michael [8].

Sequencing of the Joshua tree genome (Yucca jaegeriana) to build genomic resources for conservation.

Joshua tree is the common name given to arborescent members of the of the  Yucca  genus found primarily in the Mojave Desert of the American Southwest. Joshua trees  are a keystone species of the Mojave and an indicator for desert flora and fauna imperiled by climate change.  Like other yuccas, Joshua trees exhibit obligate pollination by yucca moths (Proxidae) making them a classical model for studies of co-evolution. Current taxonomic circumscription split Joshua trees into two species: the tall, tree-like  Yucca brevifolia  Engelm. and the short, shrub-like  Yucca jaegeriana  (McKelvey) L.W.Lenz. In addition to being morphologically distinct in overall habit, these species have diverged in floral morphology likely as a result of a recent speciation event in their pollinators leaving  Y. brevifolia  being pollinated by  Tegeticula synthetica  and  Y. jaegeriana  being pollinated by  T. antithetica.  Joshua trees are under threat due to environmental changes associated with climate change, increased intensity of frequency of fires, and changes in land use in the Southwest. In an effort to preserve these iconic plants, we are looking to present-day genetic diversity to identify potential loci of future resiliency. Here, we present a highly contiguous assembly of the  Y. jaegeriana  genome that will serve as a reference for sequencing across population diversity of Joshua trees. The genome was sequenced using HiFi PacBio to a depth of ~45X coverage. The expected genome size of this accession was ~3 Gb with n=30 chromosomes. The genome assembly is 3.1 Gb with an L50 of 8, N50 of 81 Mb, L90 of 40, and N90 of 20 Mb. Of the assembled contigs, ten contigs are telomere to telomere suggesting they represent whole chromosome sequences. In addition to being highly contiguous, the genome is very complete with 99.4% of BUSCO genes recovered in the assembly. We demonstrate some initial analyses with the genome highlighting the variation in transposon density and paralog dispersal across the characteristic bimodal karyotype of the species and other members of the   Agavoideae Bimodal Karyotype clade. The genome will serve as an invaluable resource to empower our genomic-based conservation efforts for Joshua tree.

1 - University Of Alabama , Department Of Biology, Science And Engineering Complex, 1325 Hackberry Ln, Tuiscaloosa, AL, 35401, United States
2 - USGS, Western Ecological Research Center, 418 Birch Street, Boulder City, NV, 89005, United States
3 - USGS Western Ecological Research Center, 160 Stephanie Boulevard , Henderson, NV, 89074
4 - Willamette University, Biology, Salem, Or
5 - Willamette University, Biology, 900 State Street, Department Of Biology, Salem, OR, 97301, United States
6 - University Of Hawai'i, School Of Life Sciences, 1800 East-West Road, Honolulu, HI, 96822, United States
7 - California State University Northridge, 11927 West Magnolia Boulevard, Apt 26, CR 5313, Valley Village, CA, 91607, United States
8 - University Of Alabama, 411 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States

Keywords:
genomics
Yucca
desert.

Presentation Type: Poster
Session: P2, Functional Genetics and Genomics Posters
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 5:00 PM(EDT)
Number: P2CG005
Abstract ID:1015
Candidate for Awards:None