Morphological Characterization of small, dumpy, and long Phenotypes in Caenorhabditis elegans

Abstract

The determinant factors of an organism's size during animal development have been explored from various angles but remain partially understood. In Caenorhabditis elegans, many genes affecting cuticle structure, cell growth, and proliferation have been identified to regulate the worm's overall morphology, including body size. While various mutations in those genes directly result in changes in the morphological phenotypes, there is still a need for established, clear, and distinct standards to determine the apparent abnormality in a worm's size and shape. In this study, we measured the body length, body width, terminal bulb length, and head size of mutant worms with reported Dumpy (Dpy), Small (Sma) or Long (Lon) phenotypes by plotting and comparing their respective ratios of various parameters. These results show that the Sma phenotypes are proportionally smaller overall with mild stoutness, and Dpy phenotypes are significantly stouter and have disproportionally small head size. This study provides a standard platform for determining morphological phenotypes designating and annotating mutants that exhibit body shape variations, defining the morphological phenotype of previously unexamined mutants.

Changes in body shape implicate cuticle stretch inC. elegansgrowth control

“…Previous studies theorized that the internal mechanism for sensing body size and triggering molts in C. elegans is driven, in part, by the properties of the collagen-rich cuticle [12,28]. Many cuticle collagen mutations cause morphological defects in nematode shape [36]. Some of these mutants are shorter than the wild-type but do not have differences in animal width, implying that the cuticle affects length and width independently [37].…”

Linkage mapping reveals loci that underlie differences in Caenorhabditis elegans growth

“…In the laboratory strain of C. elegans , we know many loci that quantitatively affect body size and shape. Mutations in these genes span various classes, including abnormal pharyngeal pumping (Eat), egg-laying defective (Egl), uncoordinated (Unc), abnormal dauer formation (Daf), and several cuticle and body shape classes (Dpy, Lon, Sma, Rol, Sqt) ( Mörck and Pilon 2006 ; So et al 2011 ; Cho et al 2021 ). The polygenic nature of complex traits is a recognized barrier in identifying the genes contributing to phenotypic variation in a population ( Boyle et al 2017 ; Bernstein et al 2019 ).…”

Linkage mapping reveals loci that underlie differences in C. elegans growth

“…Mutations in these genes span various classes, including abnormal pharyngeal pumping (Eat), egg-laying defective (Egl), uncoordinated (Unc), abnormal dauer formation (Daf), and several cuticle and body shape classes (Dpy, Lon, Sma, Rol, Sqt) (Mörck and Pilon 2006; So et al . 2011; Cho et al . 2021).…”

“…In the laboratory strain of C. elegans, we know many loci that quantitatively affect body size and shape. Mutations in these genes span various classes, including abnormal pharyngeal pumping (Eat), egg-laying defective (Egl), uncoordinated (Unc), abnormal dauer formation (Daf), and several cuticle and body shape classes (Dpy, Lon, Sma, Rol, Sqt) (Mörck and Pilon 2006;So et al 2011;Cho et al 2021). The polygenic nature of complex traits is a recognized barrier in identifying the genes contributing to phenotypic variation in a population (Boyle et al 2017;Bernstein et al 2019).…”