Effect of Phenotype Selection on Genome Size Variation in Two Species of Diptera

Abstract

Genome size varies widely across organisms yet has not been found to be related to organismal complexity in eukaryotes. While there is no evidence for a relationship with complexity, there is evidence to suggest that other phenotypic characteristics, such as nucleus size and cell-cycle time, are associated with genome size, body size, and development rate. However, what is unknown is how the selection for divergent phenotypic traits may indirectly affect genome size. Drosophila melanogaster were selected for small and large body size for up to 220 generations, while Cochliomyia macellaria were selected for 32 generations for fast and slow development. Size in D. melanogaster significantly changed in terms of both cell-count and genome size in isolines, but only the cell-count changed in lines which were maintained at larger effective population sizes. Larger genome sizes only occurred in a subset of D. melanogaster isolines originated from flies selected for their large body size. Selection for development time did not change average genome size yet decreased the within-population variation in genome size with increasing generations of selection. This decrease in variation and convergence on a similar mean genome size was not in correspondence with phenotypic variation and suggests stabilizing selection on genome size in laboratory conditions.

Genome Size Covaries More Positively with Propagule Size than Adult Size: New Insights into an Old Problem

“…Incisive multivariate experimental and comparative analyses are needed to unravel the various causal pathways likely involved in relationships between genome size and reproductive propagule size, somatic cell size, body size, and various other phenotypic (developmental, physiological and life-history) traits ( Figure 6 ). Artificial selection experiments may be especially valuable in this respect (e.g., [ 345 ]). Several investigators have emphasized that multiple causal pathways are likely involved in the evolution of genome size (e.g., [ 7 , 8 , 90 , 97 , 183 , 186 , 327 ]).…”

Identification and Characterization of Small RNA Markers of Age in the Blow Fly Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae)

“…Whole jars of larvae or intrapuparial samples were sampled, while control jars were used for comparison of development time. The selection response for these strains can be seen in [ 57 ] and [ 58 ].…”

“…RNA was extracted from individuals using a Qiagen miRNeasy Kit and on-column DNase treatment following manufacturer protocols (Qiagen Inc., Valencia, CA, USA) and then was stored with Superase In RNase inhibitor at −80 °C. Samples were not identified as to their sex, as there is not known to be significant differences in the development time between sexes of C. macellaria [ 58 ]. Sample concentration and quality control were assessed with a Nanodrop Spectrophotometer (Thermo Fisher Scientific Inc., Wilmington, DE, USA).…”

A review of Forensic Entomology literature in the southwestern United States

“…The genetic data and genome size was also analyzed for B. plinthopyga , finding that the female genome was larger than the male (Pimsler et al, 2014). The genome size was studied in different populations of developing C. macellaria , one that was selected for fast development and one for slow development, which found that mean genome size did not change (Hjelman et al, 2020).…”