Partnering With a Team of International Scientists Posted February 24, 2016 by Friends of the Joshua Tree Forest


Dear Friends,
I am writing to share the exciting news that Friends of Arizona Joshua Tree Forest has partnered with an international team of scientists on an initiative to sequence the genome of the Joshua Tree (Yucca brevifolia in the broad sense). The project aims to identify genes involved in coevolution with yucca moths and climate adaptation.
The project includes a social media campaign to generate public engagement, and promote public understanding of conservation genomics. You can check out the project webpage here: , follow the project on twitter here: @JTGenome, and join the Facebook group here: . 

Why Sequence The Joshua Tree Genome?

A Joshua tree reference genome would open the doors to answering many questions, of both scientific and conservation importance.

Discovering genes that allow adaptation to desert environments. The Mojave Desert contains some of the hottest and most arid regions of North America. To survive in these inhospitable environments, Joshua trees have developed an array of physiological and morphological adaptations, from thickening of the waxy cuticle on the outside the leaves, to reduced stomatal pore size, and the presence of water storage cells. Sequencing the Joshua tree genome will help to identify the genetic basis of these adaptations, and will identify existing genetic variation in Joshua trees that may allow some individuals to survive and adapt to warmer temperatures. We will combine genome-wide-association studies with gene expression assays in common gardens to determine which genes have enabled Joshua trees to survive in the Mojave.

Understanding the genetics of coevolution. Like all yuccas, Joshua trees rely on a specialized group of moths to move their pollen from plant to plant. Amazingly, female moths actively collect and distribute yucca pollen after laying their eggs in the flowers they pollinate. Yucca moths effectively farm yucca seeds as nutrition for their offspring. In exchange for reliable pollination, yuccas sacrifice some of their seeds to the moths’ larvae. Joshua tree flowers exhibit a suit of adaptations that promote active moth pollination while deterring larval consumption of all their developing seeds. The genetic bases of these adaptations, however, are currently unknown.  Sequencing of a reference Joshua tree genome would pave the way for association mapping to identify genes contributing to co-evolved adaptations to yucca moth pollination and larval seed predation.

A genomic approach to conservation. Ensuring that Joshua trees will persist into the future means preserving not only the plants themselves, but also the genetic variation that will allow them to adapt to changing climates and environments. We will use a landscape genomics approach to measure the total amount of genetic variation in different populations, and estimate genetic differentiation between populations. This information will allow us to identify which populations of Joshua tree have the greatest potential to adapt to future environmental changes, and give these areas the highest priority for conservation.

Christopher Irwin Smith
Associate Professor and Chair
Department of Biology
Willamette University
Salem, OR 97301
Lab Website:
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