Presenter Information

Clare E. VergobbiFollow

Presentation Type

Presentation - Campus Access Only

Abstract

Whitebark pine (Pinus albicaulis) is a high elevation tree in serious decline.. It is experiencing high mortality due to white pine blister rust, an exotic disease, and outbreaks of the native mountain pine beetle, as well as the effects of climate change. It is unknown how this massive mortality has altered the genetic diversity of whitebark pine populations. Furthermore, large die-offs can act as strong selection events, removing individuals with lower fitness. It is possible that survivors of mountain pine beetle outbreaks have different genotypes than trees killed and may be better adapted to current and future warmer drier climates.

This project uses Inter-Simple Sequence Repeats (ISSR), a method that detects high levels of genetic polymorphism, to test two hypotheses: 1) surviving trees differ genetically from those that are killed by the beetle, and 2) the outbreak has reduced overall genetic diversity in affected stands. Needles were collected from surviving trees after a beetle outbreak and from trees just under the minimum diameter beetles attack. The smaller trees were used a surrogate for the ‘general population’ pre-beetle selection. DNA was extracted from the needles and screened with three ISSR primers using PCR and gel electrophoresis to analyze genetic differences between individuals. Survivors and a few general population trees clustered distinct from other general population trees indicating distinct genetic differences among survivors and those selected by the beetles. This suggests that selection may be occurring in these populations as a result of the beetle outbreaks.

Information gained in this study will help develop a more informed approach to whitebark pine restoration and forest adaptation to climate change.

Category

Life Sciences

Available for download on Friday, April 24, 2020

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Apr 28th, 10:20 AM Apr 28th, 10:40 AM

Genetic differences in whitebark pine after a mountain pine beetle outbreak

UC 327

Whitebark pine (Pinus albicaulis) is a high elevation tree in serious decline.. It is experiencing high mortality due to white pine blister rust, an exotic disease, and outbreaks of the native mountain pine beetle, as well as the effects of climate change. It is unknown how this massive mortality has altered the genetic diversity of whitebark pine populations. Furthermore, large die-offs can act as strong selection events, removing individuals with lower fitness. It is possible that survivors of mountain pine beetle outbreaks have different genotypes than trees killed and may be better adapted to current and future warmer drier climates.

This project uses Inter-Simple Sequence Repeats (ISSR), a method that detects high levels of genetic polymorphism, to test two hypotheses: 1) surviving trees differ genetically from those that are killed by the beetle, and 2) the outbreak has reduced overall genetic diversity in affected stands. Needles were collected from surviving trees after a beetle outbreak and from trees just under the minimum diameter beetles attack. The smaller trees were used a surrogate for the ‘general population’ pre-beetle selection. DNA was extracted from the needles and screened with three ISSR primers using PCR and gel electrophoresis to analyze genetic differences between individuals. Survivors and a few general population trees clustered distinct from other general population trees indicating distinct genetic differences among survivors and those selected by the beetles. This suggests that selection may be occurring in these populations as a result of the beetle outbreaks.

Information gained in this study will help develop a more informed approach to whitebark pine restoration and forest adaptation to climate change.