genetic representation

Sean Hoban, Emma Spence, and Patrick Thompson, The Morton Arboretum

The Morton Arboretum seeks to improve the conservation value and genetic representation in ex situ collections by developing guidance for sampling seed. One example regards IUCN Critically Endangered Quercus boyntonii (Boynton sand post oak), which is endemic to Alabama and only occurs on exposed sandstone outcrops.In situ threats include overcrowding by invasive species, off trail disturbance by humans, and the threat of wildfires. To help safeguard this species in case wild populations are lost, we compared genetic diversity of wild Quercus boyntonii populations to ex situ collections. We collected 246 individuals from 11 locations in the wild and 77 samples from 14 botanic gardens across the United States. We used microsatellite DNA markers to quantify genetic variation existing in the wild samples and calculate the proportion of genetic variation that exists in ex situ collections. This is a direct measure of the success of the collective efforts to build conservation collections. We found that current ex situ collections capture approximately 78% of overallgenetic diversity, and 100% of common alleles. We also used a resampling technique to determine how efficient this collection is, and we showed that a smallerex situcollection may be sufficient if it is carefully planned. The overall message is that ex situ collections of a taxon spread across a number of institutions can safeguard a species’ genetic diversity. This work is part of a large, multi-institution project in which genetic variation in ex situ collections of 10 species will be quantified. Our end goal is to provide advice to the garden community about how to establish and maintain ex situ tree collections, which includes initiatives to distribute germplasm collaboratively.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018

Kim McCue, Shannon Felberg and Steve Blackwell
Desert Botanic Garden

Date Recorded: 
Friday, May 4, 2018

Funding Opportunity: BGCI/GGI-Gardens Awards Program

The Global Genome Initiative for Gardens (GGI-Gardens) is an international partnership of botanical gardens and arboreta focused on collecting herbarium vouchers from living collections and preserving their genome resources in biorepositories partnered with the Global Genome Biodiversity Network (GGBN).

Question Category: 

Funding Opportunity: BGCI/GGI-Gardens Awards Program

The Global Genome Initiative for Gardens (GGI-Gardens) is an international partnership of botanical gardens and arboreta focused on collecting herbarium vouchers from living collections and preserving their genome resources in biorepositories partnered with the Global Genome Biodiversity Network (GGBN).

Question Category: 

Dr. Sean Hoban, The Morton Arboretum, Taylor Callicrate, Species Conservation Toolkit Initiative, Chicago Zoological Society, Susan Deans, Plant Biology and Conservation Program, Northwestern University, Michael Dosmann, The Arnold Arboretum of Harvard University, Jeremie Fant, Chicago Botanic Garden, Oliver Gailing, University of Göttingen, Kayri Havens, Chicago Botanic Garden, Andrew Hipp, The Morton Arboretum, Priyanka Kadav, Michigan Technological University, Andrea Kramer, Chicago Botanic Garden, Matthew Lobdell, The Morton Arboretum, Tracy Magellan, Abby Meyer, Botanic Gardens Conservation International, Emma Spence, Center for Tree Science, The Morton Arboretum, Patrick Thompson, Auburn University Raakel Toppila, Seana Walsh, National Tropical Botanical Garden, Murphy Westwood, The Morton Arboretum, Jordan Wood, Illinois Natural History Survey, M. Patrick Griffith, Montgomery Botanical Center

Ex situ collections such as botanic gardens inspire and educate the public, provide material for scientific study, and produce material for ecological restoration. The challenge for an efficient and effective collection is safeguarding high genetic and ecological diversity in as few samples as possible, due to the relatively small resources available for conservation. A botanic garden might have resources to maintain a few to a few hundred plants of priority species in conservation collections, but not the thousands that seed banks can preserve. Providing scientifically grounded recommendations for the number of individuals that need to be conserved, and how to collect from the wild and manage collections over time, is a pressing need. Previous work using case studies and modeling of important biological traits has established the fact that some species must be sampled differently, and that widely used standard sample sizes might not be optimal practice for capturing the maximum diversity. We present here a comparative study of ex situ gene conservation in three southeastern oaks (Quercus georgiana, oglethorpensis and boyntonii) and two magnolias (M. pyramidata and asheii). Specifically, we use genetic datasets and resampling algorithms to: quantify how much genetic diversity has been captured in a global network of botanic garden collections currently, resample the wild population genetic datasets to determine how much genetic diversity could be captured by varying sample sizes, determine minimal sampling needed to capture 70% and 95% of the genetic diversity, and use a diminishing returns method to calculate optimal stopping points- when additional collection effort no longer provides sufficient gains. Between 62 and 72% of genetic diversity is currently safeguarded for the oaks, and about 80% is conserved for the magnolias. The recommended collection size depends on key decisions by curators about the type of genetic diversity that is valued, but may range from approximately 50 to 200 individuals. We hope that these findings motivate future seed collections from wild provenances for botanic garden collections and stimulate discussion on ex situ gene conservation goals and outcomes.

Date Recorded: 
Wednesday, March 4, 2020

Jordan Wood, Jeremie Fant, Andrea Kramer and Kay Havens, Chicago Botanic Garden

Genetics becomes important whenever populations become small (<100). This includes loss o fgenetic diversity from drift, increased expression of deleterious genes due to inbreeding, and limiting local adaptation. Since many species of plants are able to be seed banked, it is possible to maintain numbers well above these critical genetic thresholds. However for exceptional species, which can only be maintained as living plants, or for critically endangered species where remaining individuals are already below these numbers, the need to consider the remaining genetic diversity becomes critical. Importantly, the management focus shifts from saving a population to preserving each genetically unique individual. When you have such small numbers, it is critical to know how each individual contributes to the overall genetic diversity remaining. We are working with National Tropical Botanic Gardens (Hawaiʻi) to develop a multi-institution species management and breeding plan for Ālula(Brighamia insignis)that will ultimately support its restoration to the wild. To do this we are working with scientists at the Chicago Zoological Society to modify management software that incorporates genetics and demography information to maintain the long-term health of their captive populations of animals over the long term. Through this case study, we hope to develop collections management practices for plants that preserve important genetic diversity while identifying genetically appropriate individuals to using in crosses and that can ultimately be used to create resilient populations that can be used in reintroductions.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018