Cynthia M. Anderson

Association Between the Serotonin Transporter Triallelic Genotype and Eating Problems is Moderated by the Experience of Childhood Trauma in Women

OBJECTIVE This study investigated a potential interaction between the triallelic polymorphism of the serotonin transporter gene (SLC6A4) promoter and the experience of childhood trauma on the number of problem eating behaviors. METHOD The study sample was comprised of 439 (64.7% female) Caucasian college students (mean age = 22.49, SD = 6.12). Participants completed questionnaires that assessed eating problems and experience of trauma in childhood (ages 0-12) and donated cheek cells for 5-HTTLPR and rs25531 genotyping. RESULTS Women carrying a lower expressing allele (i.e., L(G) or S) who were exposed to higher levels of childhood trauma reported significantly higher mean numbers of eating problems (gender × genotype × trauma interaction, p = .006). DISCUSSION These results are consistent with findings that the lower expressing alleles of the SLC6A4 promoter are associated with increased sensitivity to the negative impact of childhood stressors on adult behavioral outcomes.

Serotonin transporter (5-HTTLPR) genotype and childhood trauma are associated with individual differences in decision making

The factors that influence individual differences in decision making are not yet fully characterized, but convergent evidence is accumulating that implicates serotonin (5-HT) system function. Therefore, both genes and environments that influence serotonin function are good candidates for association with risky decision making. In the present study we examined associations between common polymorphisms in the serotonin transporter gene (SLC6A4; 5-HTTLPR and rs25531), the experience of childhood trauma and decision making on the Iowa gambling task (IGT) in 391 (64.5% female) healthy Caucasian adults. Homozygosity for the 5-HTTLPR L allele was associated with riskier decision making in the first block of 20 trials (i.e., decision making under ambiguity, p = 0.004). In addition, mean IGT performance was significantly worse in blocks 3–5 (i.e., decision making under risk, p ≤ 0.05) for those participants who reported experiencing higher levels of childhood trauma. Our findings add to the growing evidence that genetic variation in the 5-HT system is associated with individual differences in decision making under ambiguity; and we report that the experience of childhood trauma is associated with relatively poor decision making under risk.

Epigenetics of drought-induced trans-generational plasticity: consequences for range limit development

Offspring phenotypes may be altered by environments that their parents lived in. These environmentally-induced trans-generational effects may be mediated by epigenetic mechanisms such as DNA methylation. Little is known about the role of such epigenetic effects in evolution; however, it is expected to facilitate evolution. To expand geographic range, it is thought that most species would have to adapt via evolution by natural selection to stressful environments beyond range boundaries. Contrary to expectations, we show that DNA methylation in an upland mustard species may underlie a drought-induced trans-generational tradeoff that may constrain the process of adaptation to stressful environments at lower elevations.

Conservation genetics of American Dipper (Cinclus mexicanus): the genetic status of a population in severe decline

American Dippers (Cinclus mexicanus) were once known to occur in streams throughout the Black Hills of South Dakota and Wyoming, but now dippers number about 50–75 individuals and reside almost exclusively in a single stream. The recent decline of the American Dipper in the Black Hills of South Dakota is thought to be due to local stream degradation. As a result of the decline of C. mexicanus in the Black Hills of South Dakota and Wyoming, the Black Hills population of American Dippers is a candidate for designation as a distinct population segement (DPS) and might warrant protection and special management. One criterion for DPS designation is genetic uniqueness. Here we present the results of a genetic assessment of the Black Hills population of C. mexicanus. Data presented here indicate that the dipper population in the Black Hills is genetically distinct from other sampled populations. Further population sampling will be needed to understand the genetic population structure of C. mexicanus throughout its range. Furthermore, the recent decline in the Black Hills dipper population should be a warning that other populations (and other species) may be experiencing similar declines and that such montane habitats are worthy of special management.

PERMANENT GENETIC RESOURCES: Development of polymorphic microsatellite loci for the endangered Topeka shiner, Notropis topeka

We have developed a set of eight polymorphic microsatellite markers for the endangered Topeka shiner, Notropis topeka. Allelic diversity at each of these loci was assessed in a single isolated population from eastern South Dakota, USA. The allelic diversity ranged from four to 15 alleles. These are the first microsatellite markers to be reported for this species. These markers are being used in a more thorough study of the population structure throughout the remaining range of this species.

Recovery and assessment of leukocytes from LR Express filters

Leukocytes, or white blood cells, are used for a variety of investigational purposes and they offer advantages over laboratory-adapted cell lines. Leukocytes that are typically discarded by blood banks during the collection of red blood cells, platelets, and plasma can often be obtained for research use. However, the available leukocytes are frequently contained within a blood filtration device, such as the Terumo LR Express (TLRE) filter. In this study, procedures were evaluated for the ability to elute viable leukocytes from TLRE filters. The recovered leukocytes were assessed for composition, growth, and functionality. The large majority (>70%) of leukocytes were eluted with a single reverse-elution procedure and the recovered cells contained representative populations of the major leukocyte subsets. Purified T cells exhibited diverse T cell receptor repertoires, characteristic growth upon mitogen stimulation, and CD4+ T cells were able to support HIV-1 propagation. Purified monocytes were able to be differentiated into phenotypically characteristic populations of macrophages and dendritic cells. Overall, TLRE filters offer an attractive source of primary human cells for research and possibly clinical purposes.