Karyotypic Variation in Two Species of Jerboas Jaculus jaculus and Jaculus orientalis (Rodentia, Dipodidae) from Tunisia

Abstract

GRANJON L. 2010. Karyotypic variation in two species of jerboas Jaculus jaculus and Jaculus orientalis (Rodentia, Dipodidae) from Tunisia. Folia biol. (Kraków) #&: 229-236. The karyotypes of the lesser Egyptian jerboa Jaculus jaculus and the greater Egyptian jerboa Jaculus orientalis from Tunisia are described and compared with available data particularly from Egypt. The species examined have a similar karyotype consisting of 2n = 48 chromosomes and a fundamental number of autosomes (NFa) varying from 88 to 90 in J. jaculus and from 84 to 88 in J. orientalis. The X chromosome is submetacentric in both species, while the Y is submetacentric in J. orientalis and acrocentric in J. jaculus. Most of the autosomes are meta/submetacentric but the small pairs 22 -23 in J. jaculus and 20-23 in J.orientalis are frequently acrocentric, yielding considerable differences in the NFa within and among species. Morphological variation in these small pairs of autosomes and/or in the Y chromosome in J. orientalis may distinguish populations of the two species from Egypt and Tunisia. The differences observed either between Egypt and Tunisia or between the Tunisian Jaculus species are probably associated with chromosomal rearrangements such as pericentric inversions or heterochromatin variation. They appear of lesser magnitude than other changes (especially molecular) that have occurred during the evolution of this genus.

Phylogeography of two cryptic species of African desert jerboas (Dipodidae: Jaculus)

“…Together with genetic differentiation, cranial morphometrics (at least in Tunisia, Ben Faleh et al ., 2010a) also support the hypothesis that the two clades correspond to two, J. jaculus and J. deserti , species. Interestingly, and contrary to what is often found in African rodents, this genetic and morphometric differentiation is not accompanied by obvious karyological differences (Ben Faleh et al ., 2010b). Based on mitochondrial sequences it can be argued that the two identified clades represent distinct species with a sympatric distribution (probably secondary) over most of their range in North Africa (Figs 1, 2).…”

Patterns of skull variation in relation to some geoclimatic conditions inthe greater jerboa Jaculus orientalis (Rodentia, Dipodidae) from Tunisia

“…Similar variations of NFa are reported in numerous African rodents (Volobouev et al, 2002;Dobigny et al, 2010). Such polymorphism, which does not affect the diploid number, is often associated with rearrangements such as pericentric inversions or heterochromatin addition (Ben Faleh et al, 2010a). This divergence between chromosomal and morphometric data analysis of J. orientalis populations examined herein is probably due to different ecological circumstances between the three climatic regions.…”

“…The absence of significant variability between populations based upon age and sexual dimorphism was also reported in numerous rodents such as Jaculus jaculus (Ben Faleh et al, 2010b, 2010c, Mastomys natalensis (Lalis et al, 2009), Rattus rattus (Ben Faleh et al, 2012a) and Malacomys edwardsi (Bohoussou et al, 2014). The 12 J. orientalis specimens that were previously karyotyped by Faleh et al (2010a;2n = 48 and NFa varies from 84 to 88) have different skull morphometrics in the three climatic regions (or morphotypes). This variation did not seem to be geographically structured, as different NFa values are observed among populations of the same locality.…”

“…In Tunisia, detailed genetic analyses by means of allozymic markers (23 loci) for six populations with representative samples per population indicated high gene flow and absence of genetic structuration (Ben Faleh et al, 2009). In addition, Ben Faleh et al (2010a) karyotyped 12 specimens of J. orientalis and reported that all of the individuals examined had a diploid number (2n = 48) and NFa varied from 84 to 88. This variation did not seem to be geographically structured, as different NFa values were observed among populations of the same locality.…”

Are cryptic species of the Lesser Egyptian Jerboa,Jaculus jaculus(Rodentia, Dipodidae), really cryptic? Re-evaluation of their taxonomic status with new data from Israel and Sinai

“…Recently, specimens from North Africa and the Middle East were intensively studied for morphometric, chromosomal, allozyme and DNA variability (Shahin ; Ben Faleh et al. , ,b,c; Ben Faleh et al. , ; Boratyński et al.…”