Maternal Loss of miRNAs Leads to Increased Variance in Primordial Germ Cell Numbers in Drosophila melanogaster, Jan-Michael Kugler, Ya-Wen Chen, Ruifen Weng, and Stephen M. Cohen. G3, September 2013 3:1573-1576; Early Online July 26, 2013, doi:10.1534/g3.113.007591
Abstract:
MicroRNAs (miRNAs) are posttranscriptional regulators of gene expression that may act as buffering agents to stabilize gene-regulatory networks. Here, we identify two miRNAs that are maternally required for normal embryonic primordial germ cell development in Drosophila melanogaster. Embryos derived from miR-969 and miR-9c mutant mothers had, on average, reduced germ cell numbers. Intriguingly, this reduction correlated with an increase in the variance of this quantitative phenotypic trait. Analysis of an independent set of maternal mutant genotypes suggests that reduction of germ cell number need not lead to increased variance. Our observations are consistent with the hypothesis that miR-969 and miR-9c contribute to stabilizing the processes that control germ number, supporting phenotypic robustness.