The Walking Forest: An Epigenetic Study of Arctic Spruce at Treeline

Overview

There has been recent photographic evidence that, as average temperatures increase, areas of Alaskan treeline, the northernmost latitude where trees are able to survive, have advanced northward. In order to understand the nature of treeline’s advancement, it is imperative to determine the molecular basis of a tree’s adaptation that allows it to survive in the harsh conditions at the very edge of treeline. Trees at Arctic treeline are exposed to a multitude of environmental stressors including severe temperature fluctuations (mid-winter, the average low temperature reaches approximately -25 degrees C, and temperatures can fall below -50 degrees C), high wind exposure as the forest thins, and spans of several months straight with no daylight. Due to their immobile nature, plants must respond to the stresses of their environment as it changes. Plants living in high stress environments have been shown to increase epigenetic modifications in an attempt to adapt their gene expression. Our study aimed to determine whether there was a correlation between a tree’s global DNA methylation levels and a tree’s latitude using samples from Picea glauca (Arctic white spruce) trees at and below the Alaskan latitudinal treeline. We hypothesized that the trees, as sessile, long-living organisms, modify their gene expression as a mechanism of stress response and environmental adaptation in the high-stress environment of latitudinal treeline. We collected needles from a variety of spruce trees at specific latitudes at and below the Alaskan treeline. After transporting the needles back to Lisman Laboratories, we measured the percent 5-mC global DNA methylation for each tree. Needles from embryonic growth and 3-5 year old needles were assessed separately; for our study, only results from old growth were analyzed to avoid potential anomalies in global methylation in the new growth. Our results found that global methylation seems to vary from the frontier of treeline to trees deep in the Boreal Forest; there was an overall trend of higher levels of methylated DNA at the northern edge of treeline, which may signify an attempt to “turn off” all but the most necessary genes in order to survive in incredibly harsh conditions.

Competition history

• AJAS 2019 Category not listed

Related projects

Closest projects by meaning, across every fair and year in the corpus.

Browse more like this

• All Plant Sciences projects
• AJAS Plant Sciences projects
• Every AJAS 2019 project