Scientists & Staff
Current ResearchConservation and restoration of Acacia koa, a valuable hardwood tree species endemic to the Hawaiian archipelago, populations is a concern that will be addressed from multiple angles. Two current projects are looking at the genetic determinants involved in the adaptation response exhibited by koa growing at varied elevations. Using cutting edge NextGeneration Sequencing (NGS) technologies, TropHTIRC researchers will be able to obtain genetic information that will help to differentiate varied populations at the level of the genome and gene expression levels as well as:
- Estimate the variation in genetics between koa populations in various regions of the Island. Acacia koa species have varied responses to climate fluctuations when grown at different elevations. It is necessary to evaluate which genes are responsible for improved survival characteristics in light of a changing climate;
- Perform a comparative analysis of koa that have developed figure to those trees that have not developed figure. Isolation and characterization of particular wood formation genes differentially regulated between the two samples may help determine the genetic basis of figure within koa wood.
My research interests are focused on comparative analysis of differentially expressed genes related to abiotic stress tolerance and wood formation in tropical hardwood populations. My methodologies involve use of in silica, ex vitro, and molecular-based data acquisition aided by field experimentation.
Previous research efforts in this field involved three distinct topics:
- Drought tolerance and water-use efficiency in poplar using stomatal density manipulation;
- Overexpression of an Arabidopsis salt tolerance gene in poplar;
- Alterations of cuticular wax gene expression to improve abiotic stress tolerance.
Prior to a career in forestry, research efforts were based in human genetics and neuroscience. The topics of interest consisted primarily of human disease conditions. I gained experience working with a variety of model research organisms.
Selected research topics are listed below:
- Characterization of genes affecting brain neuronal development using embryonic dissections for in situ hybridization experiments in G. gallus and M. musculus;
- Generation of mutants in D. rerio by artificial in vitro fertilization to study Osteogenesis Imperfecta (Brittle Bone syndrome);
- Use of whole-mount in situ hybridization and morpholino injections of M. musculus and D. rerio to study Bardet-Biedl Syndrome;
- In silico analysis of a homologue of the human glaucome gene myocilin when microinjected into C. elegans.
While these research topics are highly divergent from my current work, the techniques, qualitative and quantitative skills, and my overall work ethic have served as a solid foundation for my current research.
PUBLICATIONS (from past research)
- Gerdes JM, Zaghloul NA, Leitch CC, Lawson SS, Mitsuma N, Tan PL, Menezes LF, Hill J, Kato M, Beachy PA, Beales PL, Germino GG, Fisher S, and Katsanis N. 2007. Disruption of the basal body compromises proteasomal function and perturbs intracellular Wnt response. Nature Genetics 39:1350-1360.
- Badano JL, Leitch CC, Ansley SA, May-Simera H, Lawson SS, Lewis RA, Beales PL, Dietz HC, Fisher S, and Katsanis N. 2006. Dissection of epistasis in oligogenic Bardet–Biedl syndrome. Nature 439:326-330.
DOI's from publications where my technical assistance was acknowledged but I did not participate in the writing of the manuscript.
Why This Research is Important
Acacia koa A. Gray (koa) is a tree species endemic to all of the islands within the Hawaiian archipelago but only exists in populations of sufficient size to be called forests on Hawai'i, Kauai, Maui and Oahu. Free-range cattle grazing and over-harvesting combined with invasive grasses have severely crippled koa forests to a point where populations are continuing to decline despite several small-scale restoration efforts. Koa populations also vary along elevational transects thus attempts to determine which genetic components allow specific trees to survive conditional intolerable to other memebers of the species are urgenly needed. Climate change, invasive species (both flora and fauna), and over-harvesting have combined to severely impact koa populations. Additional research is desperately needed for the sake of the tree species, the endangered animals that depend on these trees for survival, and the native islanders that depend on the highly-prized, figured wood for their livelihood.
- American Society for Plant Biology (ASPB) (2009 - Current)
- Society for the Advancement of Chicanos and Native Americans in Science (SACNAS) (2007 - Current)
- Society for In Vitro Biology (SIVB) (2010 - 2013)
- American Society for Cell Biology (ASCB) (1999 - 2003)
- Society of Toxicology (SOT) (1999 - 2003)
Featured Publications & Products
- Lawson, Shaneka S.; Pijut, Paula M.; Michler, Charles H. 2014. Comparison of arabidopsis stomatal density mutants indicates variation in water stress responses and potential epistatic effects. Journal of Plant Biology. 57(3): 162-173.
- Lawson, Shaneka S.; Pijut, Paula M.; Michler, Charles H. 2014. The cloning and characterization of a poplar stomatal density gene. Genes & Genomics. 36(4): 427-441.
- Lawson, Shaneka; Michler, Charles H. 2014. Afforestation, restoration and regeneration -- Not all trees are created equal. Journal of Forestry Research. 25(1): 3-20.
- Lawson, Shaneka S.; Pijut, Paula M.; Michler, Charles H. 2013. Species selection in hardwoods research: variations in baseline physiological responses of select temperate hardwood tree species. Journal of Forestry Research. 24 (2): 285-292.
- Pijut, Paula M.; Lawson, Shaneka S.; Michler, Charles H. 2011. Biotechnological efforts for preserving and enhancing temperate hardwood tree biodiversity, health, and productivity. In Vitro Cellular and Developmental Biology-Plant. 47: 123-147.
Publications & Products
- Ebrahimi, Aziz ; Mathur, Samarth ; Lawson, Shaneka S.; LaBonte, Nicholas R.; Lorch, Adam ; Coggeshall, Mark V; Woeste, Keith E. 2019. Microsatellite Borders and Micro-sequence Conservation in Juglans. Scientific Reports
- Ebrahimi, Aziz ; Lawson, Shaneka S.; Frank, Graham S.; Coggeshall, Mark V; Woeste, Keith E.; McKenna, James R. 2018. Pollen flow and paternity in an isolated and non-isolated black walnut (Juglans nigra L.) timber seed orchard. PLOS ONE
- Ghanbarpour, Elmira ; Rezaei, Mehdi ; Lawson, Shaneka. 2018. Reduction of Cracking in Pomegranate Fruit After Foliar Application of Humic Acid, Calcium-boron and Kaolin During Water Stress. Erwerbs-Obstbau
- Lawson, Shaneka S.; Ebrahimi, Aziz. 2018. Development and validation of Acacia koa and A. koaia nuclear SSRs using Illumina sequencing. Silvae Genetica
- Shamlu, Fatemeh ; Rezaei, Mehdi ; Lawson, Shaneka ; Ebrahimi, Aziz ; Biabani, Abbas ; Khan-Ahmadi, Alireza. 2018. Genetic diversity of superior Persian walnut genotypes in Azadshahr, Iran. Physiology and Molecular Biology of Plants
- LaBonte, Nicholas R.; Jacobs, James ; Ebrahimi, Aziz ; Lawson, Shaneka ; Woeste, Keith. 2018. Data mining for discovery of endophytic and epiphytic fungal diversity in short-read genomic data from deciduous trees. Fungal Ecology. 9 p.
- Lawson, Shaneka S.; Bhide, Ketaki P.; Thimmapuram, Jyothi. 2018. RNAseq analysis of figured and non-figured Acacia koa wood. Current Trends in Forest Research. 2018(2): 100013. 21 p.
- Ebrahimi, Aziz ; Zarei, Abdolkarim ; Zamani Fardadonbeh, Mojtaba ; Lawson, Shaneka. 2017. Evaluation of genetic variability among "Early Mature" Juglans regia using microsatellite markers and morphological traits. PeerJ
- Lawson, Shaneka ; Pike, Carrie. 2017. Stable isotope ratios and reforestation potential in Acacia koa populations on Hawai'i. Annals of Forest Research
- Ebrahimi, Aziz; Zarei, Abdolkarim; Lawson, Shaneka; Woeste, Keith E.; Smulders, M. J. M. 2016. Genetic diversity and genetic structure of Persian walnut (Juglans regia) accessions from 14 European, African, and Asian countries using SSR markers. Tree Genetics & Genomes. 12(6): 114. 12 p.
- Lawson, Shaneka S. . 2016. Investigation of the effect of AtWIN1/SHN1 overexpression on poplar trees. Research Journal of Botany
- Lawson, Shaneka S.; Michler, Charles H. 2014. Overexpression of AtSTO1 leads to improved salt tolerance in Populus tremula × P. alba. Transgenic Research. [15 June 2014].
- Pijut, Paula M.; Beasley, Rochelle R.; Lawson, Shaneka S.; Palla, Kaitlin J.; Stevens, Micah E.; Wang, Ying. 2012. In vitro propagation of tropical hardwood tree species A review (2001-2011). Propagation of Ornamental Plants. 12(1): 25-51.
National Research Highlights
Stable isotopes in trees can be used to help determine overall tree health, nutrient levels, and optimal locations for trees to thrive. Forest Service scientists measured isotopes in koa leaves to identify the best sites for reforestation efforts on the island of Hawai’i.
Acacia koa (koa), a tropical hardwood only found in the Hawaiian Archipelago, is highly valued for its beautiful figured (with special textures or patterns) wood. The underlying factors determining amount and quality of figuring is not known. Forest Service scientists are just beginning research to solve the mystery.