Population Genetics and Spatial Structure in Two Andean Cats (The Pampas Cat, Leopardus Pajeros and the Andean Mountain Cat, L
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Chapter 7 POPULATION GENETICS AND SPATIAL STRUCTURE IN TWO ANDEAN CATS (THE PAMPAS CAT, LEOPARDUS PAJEROS AND THE ANDEAN MOUNTAIN CAT, L. JACOBITA) BY MEANS OF NUCLEAR AND MITOCHONDRIAL MARKERS AND SOME NOTES ON SKULL BIOMETRICS Manuel Ruiz-García1,, Daniel Cossíos2, Mauro Lucherini3, José Yáñez4, Myreya Pinedo-Castro1 and Bernard Angers2,5 1Laboratorio de Genética de Poblaciones Molecular-Biología Evolutiva, Unidad de Genética, Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá DC, Colombia 2Department of Genetics and Evolution, University of Geneva, Switzerland 3GECM, Universidad Nacional del Sur-CONICET, Bahia Blanca, Argentina 4Museo Nacional de Historia Natural, Santiago, Chile 5Departement de Sciences Biologiques, Université de Montreal, Montreal, Canada ABSTRACT In this chapter, we show complementary results to the works of Cossíos et al., (2009, 2012), on the genetic structure and phylogenetics of two small Andean cats, the Pampas cat (Leopardus pajeros) and the Andean mountain cat (Leopardus jacobita). In the present study we increased the samples sizes to 235 individuals for L. pajeros and 115 individuals for L. jacobita, effectively making these samples the largest to date for these two species. We analyzed five microsatellites for L. pajeros and seven microsatellites for For correspondence: [email protected], [email protected]. 2 Manuel Ruiz-García, Daniel Cossíos, Mauro Lucherini et al. L. jacobita as well as the hypervariable domain 1 (HVS-1) of the mtDNA control region for both species. The main results obtained were as follows: 1- The levels of gene diversity for L. pajeros with microsatellites were considerable higher than in L. jacobita (average H = 0.73 vs. 0.42, respectively), with the first similar to other Neotropical felids but the second one lower than other Neotropical felids and many other Neotropical mammals analyzed from this point of view. The same was recorded for mtDNA sequences, with the Pampas cat ( = 0.0513) presenting more than 10 times higher nucleotide diversity than the Andean mountain cat ( = 0.0047). The sample which could represent the putative morphological subspecies, L. p. budini, was that which yielded the highest levels of gene diversity. This could mean that this is the original L. pajeros form from which the other forms derived. Alternatively, the northern area of Argentina, where L. p. budini occurs, could be a hybridization zone among several L. pajeros forms. 2- Microsatellite heterogeneity for the Pampas cat was significant but it was relatively low with regard to the high genetic heterogeneity found for L. jacobita for microsatellites. For mtDNA, the genetic heterogeneity was very high and similar for both species. This could indicate that for the Pampas cat the gene flow is male biased, meanwhile the Andean mountain cat populations are hardly isolated in the high land deserts of the Andes and the gene flow is more restricted for both males and females. Also this analysis puts in doubt that L. pajeros pajeros and L. pajeros crucinus are two different subspecies. Furthermore, this analysis revealed that if the different gene pools determined in L. pajeros are classified as different subspecies, then four different subspecies, or at least, four different evolutionary lineages must be consider in L. jacobita. 3- The assignation analyses presented relatively low percentages of correct assignation for L. pajeros, while the percentages of adequate assignation for L. jacobita were very high. This is related with the fact that gene flow estimates among the populations of the Pampas cat are considerably higher than for the populations of the Andean mountain cat for nuclear markers. 4- L. pajeros presented more evidence of population expansions during its history for microsatellites than did L. jacobita. For mtDNA, both species did not reveal traces of population expansions and L. jacobita showed a trend indicative of a moderate bottleneck. 5- Both species showed 4-5 % of mutations with multiple steps and different mutation rates for the microsatellites employed. 6- The effective number estimates were around 10 times higher for L. pajeros than for L. jacobita independently of the procedures employed. The effective sizes for L. pajeros ranged from 80,000 to 330,000 and for L. jacobita ranged from 12,000 to 38,000. However, these estimates seem to be higher than the current census sizes. The procedures of Hill (1981) and Pudovkin et al., (1996) were not useful for effective number estimations in this case. 7- Both species presented significant spatial structure related with isolation by distance and monotonic clinal trends, but this spatial structure was more developed in L. jacobita. Around 35 % of the genetic differences were explained by the geographical distances among the populations in L. pajeros, while around 64 % of the genetic differences were explained by geographical distances in L. jacobita. 8- The northern Chilean Pampas cat population seems to be an extension of the Peruvian and north Bolivian L. p. garleppi in contradiction with García-Perea (1994), who denominated that population as a new subspecies L. colocolo wolffsohni. Nevertheless, more samples of that region are needed to have total clarity of what Pampas cat is living there. Additionally, in Bolivia, we determined the existence, at least, of two putative subspecies (garleppi and steinbachi). Finally, although molecular conclusive studies are needed, the first molecular studies indicate that the existence of a unique Pampas cat species is more probably than three different species such as García-Perea (1994) proposed. Population Genetics and Spatial Structure in Two Andean Cats … 3 Keywords: Pampas cat, Andean Mountain cat, Lynchailurus, Oreailurus, Leopardus pajeros, Leopardus jacobita, DNA microsatellites, mDNA control region, spatial structure, genetic structure, phylogenies, skull biometrics INTRODUCTION Two small and elusive cats are found in the major part of the Andes cordillera. One of them is the Pampas cat (Leopardus pajeros) and the other is the Andean mountain cat (Leopardus jacobita). These cats live in high-altitude deserts of the Andes, although the Pampas cat also lives in open grassland, evergreen forests, dense shrub lands and humid forests. However, although they frequently live in sympatry, Lucherini et al., (2009) demonstrated that the Pampas cat showed the greatest proportion of nocturnal activity, while the Andean cat was more diurnal. Such a separation of activities supports the temporal niche segregation hypothesis between these two Andean felids. Aditionally, Napolitano et al., (2008) showed, in Chile, low levels of prey partitioning between both cat species because there was a wide overlap in diet composition (82 %), with the mountain viscacha (Lagidium viscacia) being the most important prey species for both (93.9 % for the Andean cat and 74.8 % for the Pampas cat, respectively). They also determined that the Andean cat’s scats increased with altitude and slope of the mountains, but there was a substantial geographic overlap in the distribution of both felines. The Pampas cat was included within the Lynchailurus genus (-Severtzov, 1858-) and it is distributed from Ecuador to southern Patagonia in Argentina and Chile. This species seems to be closely related to Leopardus tigrinus by means of the mtDNA genes 16SrRNA, ATP8 and NADH5 within the ocelot linage (Johnson et al., 1998, 1999). How many species or subspecies are included within Lynchailurus is a matter of debate. For instance, Cabrera and Yepes (1940) speculated about the possible existence of two species, the pajeros cat (Lynchailurus pajeros), basically distributed throughout Argentina, and another the “kudmu” or Molina colocolo cat (Lynchailurus colocolo), from Chile and northern Argentina, throughout Matto-Grosso, and Peru up until Ecuador. However, these authors also speculated with the possibility that they were unique species and that the study of the exemplars from Catamarca and northern Argentina could be determinant in demonstrating that they are effectively unique species. More recently, García-Perea (1994) proposed the existence of three species within Lynchailurus using meticulous skull morphology, biometrics and skin analyses: 1) L. pajeros- Desmarest 1816-, which occurs in the Andes high elevation steppes of Ecuador, Peru, Bolivia, Argentina (eastern slope of the Andes) to southern Patagonia in Chile and Argentina in lowland levels, shrub land and dry forests. The type locality was based on Azara’s account in Buenos Aires province between 35-36°; 2) L. braccatus (Cope 1889) found in southern and south western Brazil, Paraguay and Uruguay in humid and warm grassland and forested areas. The type locality is the state of Rio Grande do Sul. Allen (1919) restricted it to Chapada at Matto Grosso in Brazil. 3) L. colocolo (Molina 1782) was found at middle elevations in central Chile (with the type locality in Valparaiso province) and in high elevation steppes in northern Chile at the Andes western slopes. 4 Manuel Ruiz-García, Daniel Cossíos, Mauro Lucherini et al. Within each one of these species, García-Perea (1994) determined several subspecies. L. pajeros has seven subspecies (1a through 1f ): 1a) L. pajeros thomasi -Lönnberg 1913- has a type locality “near Quito” and has had its samples obtained from the Napo and Pichincha provinces in Ecuador. 1b) L. p. garleppi- Matschie 1912- has a type locality from Cuzco and the Apurimac area in southern Peru with a distribution