An Intronic Polymorphism in couch potato Is Not Distributed Clinally in European Drosophila melanogaster Populations nor Does It Affect Diapause Inducibility

Abstract

couch potato (cpo) encodes an RNA binding protein that has been reported to be expressed in the peripheral and central nervous system of embryos, larvae and adults, including the major endocrine organ, the ring gland. A polymorphism in the D. melanogaster cpo gene coding region displays a latitudinal cline in frequency in North American populations, but as cpo lies within the inversion In(3R)Payne, which is at high frequencies and itself shows a strong cline on this continent, interpretation of the cpo cline is not straightforward. A second downstream SNP in strong linkage disequilibrium with the first has been claimed to be primarily responsible for the latitudinal cline in diapause incidence in USA populations.Here, we investigate the frequencies of these two cpo SNPs in populations of Drosophila throughout continental Europe. The advantage of studying cpo variation in Europe is the very low frequency of In(3R)Payne, which we reveal here, does not appear to be clinally distributed. We observe a very different geographical scenario for cpo variation from the one in North America, suggesting that the downstream SNP does not play a role in diapause. In an attempt to verify whether the SNPs influence diapause we subsequently generated lines with different combinations of the two cpo SNPs on known timeless (tim) genetic backgrounds, because polymorphism in the clock gene tim plays a significant role in diapause inducibility. Our results reveal that the downstream cpo SNP does not seem to play any role in diapause induction in European populations in contrast to the upstream coding cpo SNP. Consequently, all future diapause studies on strains of D. melanogaster should initially determine their tim and cpo status.

Phosphatase of Regenerating Liver-1 Selectively Times Circadian Behavior in Darkness via Function in PDF Neurons and Dephosphorylation of TIMELESS

“…In contrast, they have no alteration of evening activity phase under long (18:6) photoperiods. These photoperiods approximate those that would be experienced by wild Drosophila melanogaster at more extreme latitudes (e.g., > 55 N; see Zonato et al, 2016 94 ). We hypothesize that PRL-1 defines a molecular pathway through which the clock adjusts behavioral phase in response to different photoperiods.…”

Aminergic Signaling Controls Ovarian Dormancy in Drosophila

“…Although the “high-dormancy” allele cpo 347V 102 , 103 was found to be present in homozygous state in the ple 4 /+ strain, this mutant exhibits a very low level of dormancy, so that the cpo SNP is unlikely to have a confounding effect on our results for ple 4 (see Supplementary Table S1 ). All other experimental genotypes (e.g.…”

A Semi-natural Approach for Studying Seasonal Diapause in Drosophila melanogaster Reveals Robust Photoperiodicity

“…One way of overcoming such small temperature changes is to place flies of the same genotype in the same light box, but covered in foil, so the flies are exposed to any photoperiodically induced temperature fluctuations, but in DD (Tauber et al, 2007, Pegoraro et al, 2014, Zonato et al, 2016). Under these conditions, these covered flies show no photoperiodic diapause so the temperature cycle on its own does not create one.…”