Wyngaard, G. A. National Science Foundation, gwyngaar@nsf.gov
Rouse, N. M. James Madison University, gasserss
Colliver, E. James Madison University, none
Domangue, R. J. James Madison University, domangrj@jmu.edu
Rasch, E. M. James H. Quillen College of Medicine, emrasch@worldnet.att.net

 
GENOME SIZE, DEVELOPMENTAL RATE, AND BODY SIZE IN FRESHWATER CYCLOPOID COPEPODS
 
We investigated the role of genome size, measured as pg of nuclear DNA/cell, in influencing development and body sizes in five freshwater cylopoid species. Our line of thinking posits that genome size affects cell size, which influences cell division rates and consequently organismal growth rates and body sizes. Smaller genomes are predicted to yield faster rates of development and smaller body sizes. Species with genome sizes ranging from 0.8 - 4.1 pg DNA were reared in the laboratory under defined conditions at 15, 22 and 30 C in order to examine growth parameters under the range encountered in nature. We found that species with smaller genomes matured faster. An expanded data set of 10 species revealed a positive, significant relationship between genome size and adult female body size. Chromatin diminution, the excision of large proportions of the presomatic genome during embryogenesis in some copepods, is proposed as one mechanism that regulates genome size, and hence contributes to the life history variations observed in nature. Three explanations of the variation in genome size and related life history traits are discussed: 1) prevalence of chromatin diminution, 2) phylogenetic structure, and 3) nucleotypic selection that may influence life history variation and fitness.
 
Day: Thursday, Feb. 4
Time: 04:15 - 04:30pm
Location: Hilton of Santa Fe
 
Code: SS24TH0400H