E. Nevo et al., Genotypic and phenotypic divergence of rodents (Acomys cahirinus and Apodemus mystacinus) at "Evolution Canyon": Micro- and macroscale parallelism, ACT THERIOL, 1998, pp. 9-34
Genetic allozyme and RAPD diversities were examined for ecological-genetic
patterns in two rodents, the spiny-mouse Acomys cahirinus (Desmarest, 1819)
and woodmouse Apodemus mystacinus (Danford and Alston, 1877), from the eco
logically contrasting opposite slopes of the Lower Nahal Oren microsite, Mt
. Carmel, Israel, designated by us "Evolution Canyon". Likewise, morphologi
cal measurements were compared. Samples of both rodent species were collect
ed from six stations: 3 (upper, middle and lower) on the "tropical" xeric S
outh-facing slope (SFS) and 3 on the opposite "temperate" mesic North-facin
g slope (NFS) which vary dramatically physically and biotically. Higher sol
ar radiation on the SFS than on the NFS makes it warmer, drier, spatiotempo
rally more heterogeneous and climatically more fluctuating and stressful th
an the cooler and more humid NFS. Consequently, the SFS exhibits an open pa
rk forest representing an "African" savanna landscape, in sharp contrast wi
th the "European" lush liveoak maquis forest. Inter- and intraslope allozym
e, RAPD, and morphological divergence was found in both rodents. Local vari
ation in solar radiation, temperature and aridity stress caused interslope
and intraslope adaptive genotypic (proteins and DNA) and phenotypic (morpho
logical, physiological and behavioural) differences paralleling regional pa
tterns across Israel in Acomys and in northern and central Israel in Apodem
us. This suggests that, at both the micro- and macroscales, diversifying na
tural (microclimate) selection appears to be the major evolutionary driving
force causing inter- and primarily SFS intraslope adaptive genotypic and p
henotypic divergence. "Evolution Canyon" proved in small rodents, as previo
usly in other organisms, an optimal model for unravelling evolution in acti
on across life and organization.