Terrence Sylvester

Biology graduate student - Blackmon Lab - Department of Biology - Texas A&M University

Education and Experience

PhD in Biology (2017 - present)

Texas A and M University, College Station, TX, USA

Broad-scale structural evolution in invertebrate genomes and the population genomics of jewel scarabs in the southwestern US.

Advised by: Dr Heath Blackmon

Bsc in Molecular Biology and Biotechnology (2011 - 2015)

University of Peradeniya, Peradeniya, Sri Lanka

Phylogenetic relationships and species boundaries of a clade of diminutive shrub frogs (Rhacophoridae: Pseudophilautus).

Advised by: Dr Madhava Meegaskumbura


Evolution of chromosome number

Genome structure, at a fundamental level, can be described by the division of the genome into a discrete number of chromosomes and further divided into autosomes and sex chromosomes. An array of mechanisms or selection pressures can lead to changes in both of these characteristics of genomes. Meiotic drive, segregation mechanisms, sexual antagonism, epistasis, benefits of higher or lower recombination, and drift have all been invoked to explain changes in the number of chromosomes and the proportion of the genome that is sex linked through sex chromosomes. Despite over a century of work, this level of genome organization has been resistant to broad generalizations that can explain the striking variation we observe among species. I will use large comparative phylogenetic approaches to determine the degree to which rates of chromosome number and sex chromosome system evolution vary among orders of insects. I will also use these approaches to infer whether mutations that have led to divergence in chromosome number are deleterious, neutral, or beneficial.

Population genetics of Chrysina gloriosa

As climate changes many species develop discontinuous distributions. When a species is separated into many isolated demes the risk of local extinction increases. Chrysina gloriosa is a jewel scarab restricted to high elevations in west Texas, southern New Mexico, and southern Arizona where it feeds on several species of trees in the Juniperus genus. This beetle is highly sought after by collectors and is one of the most charismatic insects in North America. Despite this there is currently no population genetic data that would allow for estimates of the health or resiliency of populations. Using population genomic data, I will determine the degree of gene flow among populations of the scarab jewel beetle Chrysina gloriosa across the southwestern United States and determine the landscape characteristics that best predict isolation of demes.



Jonika, M. M., Alfieri, J. M., Sylvester, T., Buhrow, A. R., & Blackmon, H. (2022). Why not Y naught. Heredity, 1-4. open access


Sylvester, T., Hjelmen, C.E., Hanrahan, S.J., Lenhart, P.A., Johnston, J.S. and Blackmon, H., 2020. Lineage-specific patterns of chromosome evolution are the rule not the exception in Polyneoptera insects. Proceedings of the Royal Society B, 287(1935), p.20201388. open access


Sendanayake, L., Sylvester, T., De Silva, U.H.A.J., Dissanayake, D.R.R.P., Daundasekera, D.M.K.C. and Sooriyapathirana, S.D.S.S., 2017. Consumer preference, antibacterial activity and genetic diversity of ginger (Zingiber officinale Roscoe) cultivars grown in Sri Lanka. Journal of Agricultural Sciences–Sri Lanka, 12(3). PDF

Gunarathne, W. A. L. N., Sylvester, T.P., Madhukalpani, O. V. S., Dissanayake, D. R. R. P., Chamikara, M. D. M., & Sooriyapathirana, S. D. S. S., 2017. Characterization of lead and vine morphological diversity, phytochemical composition and antibacterial activity in the lead extracts of six Piper betle L. cultivars in Sri Lanka. Rajarata University Journal, 4(2):3-22 PDF