Vol.:(0123456789) 1 3 Genetica https://doi.org/10.1007/s10709-018-0035-x ORIGINAL PAPER Climatic adaptation of chromosomal inversions in Drosophila subobscura Maria Galludo 1  · Jordi Canals 1  · Laura Pineda‑Cirera 1  · Carla Esteve 1  · Maria Rosselló 1  · Joan Balanyà 1,2  · Conxita Arenas 3  · Francesc Mestres 1,2 Received: 18 May 2018 / Accepted: 21 August 2018 © Springer Nature Switzerland AG 2018 Abstract Drosophila subobscura is a species with a rich chromosomal polymorphism which is adaptive to diferent climatic condi- tions. 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 mean ), maximum temperature (T max ), minimum temperature (T min ), humidity (Hm) and rainfall (Rf). As expected, no signifcant variation in inversion frequencies were detected over this short period of time. However, from a climatic point of view it was possible to diferentiate ‘warm’ and ‘dry’ from ‘cold’ and ‘humid’ samples. The joint study of maximum (T max ) and minimum (T min ) temperatures was a key element to understand the efect on adap- tation 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. Keywords Chromosomal inversions · Adaptation · Selection · Temperature · Rainfall · Humidity · Global warming Introduction In a large number of organisms, chromosomal inversions have played a key role on their adaptation, being the Dros- ophila genus the most studied (Dobzhansky 1970; Sperlich and Pfriem 1986; Krimbas and Powell 1992, 2000; Pow- ell 1997; Hofmann et al. 2004; Hofmann and Rieseberg 2008; Franks and Hofmann 2012). Because of its rich chro- mosomal inversion polymorphism, D. subobscura can be considered a model species in these studies (Krimbas 1992, 1993). Although the chromosomal inversions of this species were studied since the 30s of the last century (Zivanovic et al. 2016), the crucial point was the detection of latitudinal clines (Krimbas and Loukas 1980). There were two possible explanations for these clines: the inversions could be either adaptive with latitude or they could be a consequence of historic events. The colonization of both, North and South America by this species in the late 70s provided an answer. In both colonized regions, the latitudinal clines of the chro- mosomal inversions were reproduced in the same sense that those recorded in the Palearctic region (Prevosti et al. 1985, 1988, 1989). Thus, the adaptive origin of the clines seemed to be the most plausible explanation. However, a crucial point remained unanswered: which of the environmental factors related with latitude are the target of natural selection? Menozzi and Krimbas (1992) carried out a detailed study to answer this question. They Maria Galludo, Jordi Canals, Laura Pineda-Cirera, Carla Esteve and Maria Rosselló contributed equally to this research. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10709-018-0035-x) contains supplementary material, which is available to authorized users. * Francesc Mestres fmestres@ub.edu 1 Departament de Genètica, Microbiologia i Estadística, Secció Genètica Biomèdica, Evolució i Desenvolupament, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain 2 IRBio-Institut de Recerca de la Biodiversitat, Universitat de Barcelona, Barcelona, Spain 3 Departament de Genètica, Microbiologia i Estadística, Secció Estadística, Universitat de Barcelona, Barcelona, Spain