Research


CGRI’s current research includes:

1. An Ultra-high density genetic map of Cannabis

Genetic maps -the arrangement of genes and their particular positions into chromosomes- provide indispensable information about the location of and distances between genes, which then allows for informed breeding decisions that can be used to rapidly combine the desired traits of interest into a single strain. This project will sequence two divergent lines, one C. sativa and one C. indica, as well as 96 to 142 hybrids of those lines, to make a very high quality genetic map. This will place the existing, highly fragmented genome assemblies onto chromosomes, and correct any large errors from the genome assemblies themselves. We will also associate important phenotypes –the physical observable characteristics- with chromosomal regions, to help identify how the major genetic differences between the parents lead to variation in secondary compound production, growth rate and architectural differences. This is called QTL mapping, and will tell us which chromosomal regions contain genes with substantial effects on each of the traits we measure, enabling more efficient breeding, using marker-assisted selection in future and ongoing crosses. 

2. History, phylogeny and phylogeography of Cannabis

This project will sequence numerous pure C. sativaC. indica, and C. ruderalis accessions and heirloom varieties to develop our understanding of the relationships among the major lineages within the genus, the spread of Cannabis throughout the globe, and rates of historical hybridization between the named species. This will help identify important genetic variation that could be used for breeding purposes, as well as answering basic science questions about the genus, such as its origins and taxonomic classification, which is a topic of controversy among biologist. 

3. The hybrid origins of modern Cannabis cultivars

This project focuses on the more recent breeding work that has been done in the genus, to identify which genomic regions in each modern cultivar come from C. indicaC. sativa, C. ruderalis or other yet unnamed lineages. This will inform us about where key regions of the genome come from, identify the history and relationships among lines, and enable us to identify commonalities and differences at the genetic level that may explain similarities and variation in important traits. Understanding the origins of the Cannabis cultivars will undoubtedly complement the QTL mapping in project 1, helping to refine and improve our understanding of associations between particular genomic regions and key traits. 

 
4. Morphologic differences between Cannabis strains

In this project, we’re engaging the public in the scientific process of understanding whether indeed morphologic differences between the commonly used Cannabis strains (or species) exist. Even though we are uncertain of the number of Cannabis species and we are unsure we can find pure accessions because most of the plants have been hybridized, we hope to establish whether true differences in leaf shape between the common plants occur. We hope to validate common assertions about differences in shape between Cannabis species. The inability to obtain pure wild accessions could prevent us from establishing the real variation between the species, however we will be able to determine shape variation between commonly used plants.

Eventually, we would like to include leaves from Hops, (Humulus) which is the closest relative to Cannabis in order to understand how the shape of these two related species has changed since their divergence.

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These projects together will revolutionize Cannabis breeding, bringing the genetic tools and resources up to the level of all but a handful of crops.  Additionally, by increasing our knowledge of the relationships among and within Cannabis species, breeders can more effectively understand and utilize these tools.