Tag: Kirstin Sterner

The Flexibility of Gestural Communication in Bornean Orangutans (Pongo pygmaeus) in Kalimantan Tengah

Presenter: Cudmore (Anthropology)

Mentor: Kirstin Sterner

Oral Presentation

Panel B: “Vertebrate Expression” Walnut Room

Concurrent Session 3: 1:45-3:00pm

Facilitator: Chris Moe

Great ape communication research attempts to reveal the cognitive abilities of our closest living relatives and to inform our understanding of the evolution of human language. Although great ape gestural communication has been well documented, relatively few studies are specific to the orangutan. The aim of this study was to determine if rehabilitant orangutans (Pongo pygmaeus) at the Orangutan Care Center and Quarantine (Pasir Panjang, Indonesian Borneo) use distinct gestures toward other orangutans versus toward humans. Because orangutans are tree-living species whose arms are typically not free to gesture, we predicted that orangutan gestures are adapted to employ the whole body. Using 59 sub-adults in 18 different home enclosures, we examined gestural types and frequencies in comparisons of orangutan-orangutan and orangutan-human communication. Orangutan-human trials were run with both the experimenter facing and non-facing to further measure gestural flexibility. Our results show that 92% of orangutan-human gestures were made with the limbs, while the majority (46%) of orangutan- orangutan gestures were facial. When the human experimenter was facing, 76% of gestures were visual, while when non-facing, only 7% were visual. Our results suggest that limb gesturing toward the experimenter may be partly due to rehabilitant orangutans learning that caretakers respond more readily to anthropocentric gestures, like arm/hand pointing. Our findings demonstrate that these orangutans use gestures flexibly.

Optimization of DNA Extraction from Dried Blood Spot Samples for Use in a Telomere Length Assay

Presenter: Devan Compton

Mentors: Kirstin Sterner and Josh Snodgrass, Anthropology

Poster: 13

Majors: Anthropology and Psychology 

Telomere length (TL) is a marker of senescence, yet little is known about the specific factors that influence the performance of the TL assay. The World Health Organization’s study on global AGEing and adult health (SAGE) is investigating patterns of aging. As part of this study, dried blood spots (DBS) are being collected from adults in six countries in regions of different economic development. Before measuring TL, it is necessary to assess DNA quality obtained from DBS under various conditions. We tested if storing DBS at -20°C allows for recovery of optimal amounts of high-quality genomic DNA compared to -80°C. As DBS collected from finger pricks vary in size, we also considered the size of DBS (25uL vs. 50uL) to determine whether size affects the quality and quantity of the DNA extracted. Preliminary results indicate that 3.2mm (1/8”) punches from 50uL DBS yield nearly twice the amount of extractable DNA as 3.2mm punches from 25uL DBS. Additionally, DBS stored in a -80°C freezer yield approximately 47% more double-stranded DNA than DBS stored in a -20°C freezer. Lastly, we plan to determine the minimum quantity of DNA (three, four or six 3.2mm DBS punches) necessary to perform a successful TL assay. Methodological issues are key considerations in epidemiological research. This study will allow for optimal collection of DBS for DNA extraction as well as downstream use of the DNA in assays such as the TL assay.

Rationalizing the Ratio Difference: Analysis of Molecular Factors Related to Primate Skeletal Muscle Fiber Type

Presenter(s): Frankie Lewis

Faculty Mentor(s): Kirstin Sterner

Oral Session 4 S

Bipedalism is a defining human characteristic, and many distinctive human traits increase efficiency when walking or running. While most research has focused on the skeleton, fewer people have investigated the role of muscular changes on human bipedal evolution. In muscle, slow-twitch fibers produce energy more efficiently and are better for endurance activities, whereas fast-twitch fibers consume more energy and are advantageous for activities requiring short bursts of power. In general, quadrupeds have more fast-twitch fibers and bipeds have more slow-twitch fibers, but it is still unclear how evolution shaped these patterns. My research addressed this gap in knowledge by characterizing a set of candidate genes that encode proteins that play a role in fiber type. First, I compared the protein-coding sequences of five candidate genes in 23 primates to test if differences at the DNA level are associated with differences in locomotion. Second, I tested if these genes are expressed differently in the muscle tissue of quadrupeds vs. bipeds. The structure of each muscle fiber is generally conserved between species, whereas the abundance ratio is not. Therefore, I predicted that differential expression, not sequence variation, is the main source of the fiber-type ratio variation. Preliminary data suggests these genes are highly conserved and there are a number of differentially expressed genes in primate muscle tissue. Reconstructing the evolutionary history of this trait is important for understanding the evolution of human bipedalism and identifying genes involved in fiber type may also inform our understanding of muscular diseases.

Testing the Centromere-Drive Hypothesis in Primates.

Presenter(s): L. Gomez Gomez

Faculty Mentor(s): Kirstin Sterner & Emily Beck

Poster 52

Session: Sciences

Chromosomal centromeres play a critical role in the process of cell division. Centromeres act as binding sites for microtubules that pull chromosomes apart during mitosis and meiosis. Despite this conserved function, the centromeres themselves can vary in size and sequence content between species. Rapid evolution in these regions can also drive rapid evolution in centromere- associated proteins. Previous work has suggested these rapid changes are likely to accumulate in one of two essential centromere components; either CENP-A or CENP-C. Through compensatory coevolution, positive selection can subsequently cascade into other essential protein complexes resulting in hybrid incompatibility. Cascading selection from the centromere to CENP-A was previously reported in Drosophila by Beck et al. 2015 demonstrating the extension of positive selection to the essential Condensin I complex (SMC2, SMC4, NCAPD2, NCAPG, NCAPH orthologs). To test if kinetochore-associated proteins evolve rapidly in other animals, we examined the sequence of CENP-A and CENP-C and their associated protein complexes, Condensin I and Mis12 (DSN1, MIS12, NSL1, PMF1) respectively, across primates. Sequences were mined from publicly available genomes (21-25 individual species per gene), aligned using Clustal-Omega and manually checked in Mesquite to ensure that protein-coding sequences conformed to codon boundaries. We then used the codeml (PAML) to test for positive selection. Our preliminary data suggests CENP-C may be evolving rapidly showing evidence of positive selection in components of Condensin1 and Mis12 complexes. This finding supports the centromere-drive hypothesis, which suggests the presence of an evolutionary tug-of-war between centromeric DNA and centromere-associated proteins that may shape karyotype evolution.