Climatic adaptation of chromosomal inversions in Drosophila subobscura

Abstract

Drosophila subobscura is a species with a rich chromosomal polymorphism which is adaptive to different climatic conditions. Five samples of the Font Groga population (Barcelona, Spain) were sampled in autumn during 5 consecutive years (2011-2015) to obtain their inversion chromosomal polymorphism, and climatic data of several meteorological variables were also collected. The aim was to analyze the adaptive potential of inversions with regard to climatic variables, being the most relevant: mean temperature (T), maximum temperature (T), minimum temperature (T), humidity (Hm) and rainfall (Rf). As expected, no significant variation in inversion frequencies were detected over this short period of time. However, from a climatic point of view it was possible to differentiate 'warm' and 'dry' from 'cold' and 'humid' samples. The joint study of maximum (T) and minimum (T) temperatures was a key element to understand the effect on adaptation of many inversions. It was also observed that temperature had to be considered in conjunction with humidity and rainfall. All these factors would condition the biota of D. subobscura habitat, and chromosomal inversions could provide an adaptive response to it.

Rate of change for the thermal adapted inversions in Drosophila subobscura

“…In this study, its frequency did not change over time and did not deviate from the prediction of genetic drift model. Almost absence of frequency change for this inversion was also detected in a five years study in Barcelona (Galludo et al 2018), indicating a particular behavior that deserves to be studied in future researches. Finally, two inversions described as not related with thermal adaptation (U 1+2+6 and E 8 ) also deviate from Wright-Fisher expectations.…”

“…Orengo and Prevosti (1996) pioneered this research trying to answer this interesting biological question: what is the response of selection acting on inversions in front to climatic change? Later, other investigators working with this species confirmed their results and added more information to this fundamental and very current issue (Rodríguez-Trelles and Rodríguez 1998;Solé et al 2002;Balanyà et al 2004Balanyà et al , 2006Balanyà et al , 2009Rezende et al 2010;Orengo et al 2016;Galludo et al 2018). We focused to analyze this evolutionary problem in another area of the Palearctic region, the Balkans.…”

Local adaptation at fine spatial scale through chromosomal inversions and mito-nuclear epistasis: Findings in Drosophila subobscura (Diptera: Drosophilidae)

“…Thermal tolerance is of immense importance for survival, since temperature is quite variable in moderate climates . The importance of temperature, especially T min and T max, was confi rmed in this species when inversion polymorphism was analysed in one population in fi ve consecutive years (Galludo et al, 2018).…”

Global warming and chromosomal inversion adaptation in isolated islands: Drosophila subobscura populations from Madeira

“…Four groups are manifestly differentiated: from left to right it is possible to observe the collections from Madeira, the group of Balkan populations, the remaining European collections and the American populations. European populations are distributed along the second axis and follow a clinal distribution, with Mediterranean samples at the (Prevosti 1972;Larruga et al 1983;Mestres et al 1998;Solé et al 2002;Balanyà et al 2003Balanyà et al , 2004Araúz et al 2009;Fragata et al 2010;Calabria 2012;Galludo et al 2018). bottom, central and north European at the top. American populations are separated, due to the strong founder event, and are sorted along latitude.…”