Лев Юрьевич Ямпольский (Lev Yu. Yampolsky)

Selected Publications

Contacts

http://faculty.etsu.edu/yampolsky/ http://faculty.etsu.edu/biology East Tennessee State University Johnson City TN 37614-1710 Phone 423-439-4359 Fax 423-439-5958 E-mail: yampolsk@mail.etsu.edu

Education

Teaching

Research Interests

Mutation rates in Drosophila. Among all things we don't know about Drosophila is, surprizingly, the mutation rate. I am currently accumulating mutations with visible eye phenotypes. The goal is to identify and sequence mutant genes, obtaining mutation rate per nucleotide and mutational parameters.

Evolution of mating systems. I am developing a model of joined evolution of genes responsible for the frequency of remating in females and genes responsible for high fecundity (high performance in sperm competition) in males. Deleterious mutations causing lower male fertility are under stronger stabilizing selection when remating frequency is high (promiscous / polyandrous mating system) than when remating is low (monogamy or polygyny). Remating is usually associated with some cost; this cost can be offset in case of high frequency if low fertility males it he population. A simple analytical model predicts oscillations of remating frequency and male fertility around an unstable equilibrium under a restricted set of parameters and a stable equilibrium with monogamy and low frequency of male infertility under most conditions. I am currently working on an individual-based approach aiming to relax some of the assumptions of the analytical model. Click on thumbnails for higher resolution images:

Amino acid Exchangeability. Not all amino acid substitutions are made equal. Some substitutions are conservative, others are radical. One way to quantify this is too look at site-directed mutagenesis studies in which every amino acid in a protein (or an unbiased subset of amino acids) has been substituted (one at a time) and the effects of this substitution of protein function or organism fitness measured. Combining these data in a single amino acid substitution matrix allows to address some interesting questions bout protein evolution. This project is a continuing cooperation with UMD/NIST Center for Advanced Research in Biotechnology

Future projects for graduate stutents: (and research-oriented undergraduates)
These are plans for next three to five years.

1. Genetic characterization of naturally occurring and spontaneous mutations causing eye color, size and texture phenotypes in Drosophila. This project will involve classical genetics approaches (complementation, deletional mapping, etc.), bioinformatics approach, and, (depending on availability of funding) molecular characterization of mutant genes (transposon activity detection by Southern blotting, indel and substitution detecting by SSCP and sequencing).
2. Game theory approaches to reproductive strategies. Reproductive success of many strategies such as mate guarding or intraspecific nest parasitism is frequency-dependent. We will use continuous multiplayer game theory methods to develop models predicting evolutionary fate of such strategies.
3. Population structure of species undergoing speciation processes within Lake Baikal (Siberia) endemic amphipod species flock. This project is heaving dependent on external funding (proposal pending with NSF). If funded it will involve two field seasons on Lake Baikal and ample amount of laboratory work (microsatellite and allozyme markers).
4. Comparison of amino acid substitution patterns in proteins under different strength of stabilizing selection. (In cooperation with A. Kondrashov, NCBI.) Recent developments in protein science gave us now ways to characterize amino acid exchangeability in protein sequences. I am planning to investigate patterns of amino acid substitutions juxtaposing fast evolving proteins (e.g. self-incompatibility proteins) vs slow evolving proteins; orthologs vs. paralogs; essential (clinically important) genes vs. non-essential genes.
5. Zooplankton of Tennessee Valley Authority lakes and record of novel environment colonization in lake sediments (In cooperation with D. Simberloff, UT-Knoxville). TVA lakes present a wonderful opportunity to study the processes of colonization of novel habitats by various organisms. The lakes have been around for long enough to have an interesting colonization history and yet they are young enough to observe these processes as they continue. In addition to theoretical interest, naturally occurring colonization of TVA lakes should be of interest to TVA itself, since this process is part of how TVA activities shape the environment.

Research Group

• Jessica Minton, undergraduate student, ETSU. Project: sperm competition in Drosophila. Expected to graduate in Dec 2003.
• Gloria Simons, undergraduate student, ETSU. Project: Identification of segregating and spontaneous mutations causing visible eye phenotypes in Drosophila. expected to graduate in May 2004.
• Linsey Simpson, undergraduate student, ETSU. Project: causes of infertility in natural populations of Drosophila.
• Jeff Stirman, undergraduate special, ETSU. Projects: 1. Accumulation and screening of spontaneous mutations causing visible eye phenotypes in Drosophila. 2. Mathematical modeling of the evolution of mating systems.

Selected Publications

1. Yampolsky LY and A. Stoltzfus. 2003. Amino acid exchangeability from experimental data. In review.
2. Yampolsky LY and A. Stoltzfus. 2001. Bias in the introduction of variation as an orienting factor in evolution. Evolution and Development 3(2):73-83
3. Yampolsky LY, L. E. Pearse and D. E. L. Promislow. 2001. Deleterious mutations with age-specific effects. I. Mortality. Genetica. 110:11-29.
4. Galimov Ya. R. and L. Yu. Yampolsky. 1998. Optimal strategies of investments into resting stages in unpredictable seasonal environment. Archiv fur Hydrobiologie Spec. Issues Adv. Limnol. 52: 313-326.
5. Shabalina S. A., L. Yu. Yampolsky and A. S. Kondrashov. 1997. Rapid decline of fitness in panmictic Drosophila populations under relaxed selection. Proc. Natl. Acad. Sci. 94: 13034-13039.

Field trips

Lake Baikal. In summer 2002 I took a small class of students to a field trip to Lake Baikal in Siberia - the oldest, deepest, largest (by volume) lake on Earth, which, as many other ancient lakes, harbors a unique and highly diverse fauna. Watch for announcements of further trips here.

ї National Geographic Society