Do B chromosomes affect fecundity in yellow-necked mice Apodemus flavicollis (Rodentia, Mammalia)?

The effects of the presence of B chromosomes on fecundity of the yellow-necked mouse Apodemus flavicollis were studied in 46 females without and 28 with Bs from four localities in Serbia. Uterine inspection showed that there was no significant difference in the mean number of scars and embryos between females with and those without Bs. Thus, B chromosomes do not appear to affect the fecundity of females carrying them, indicating that the presence of Bs does not affect fitness characteristics.B hromozomi su dodatni hromozomi u odnosu na standardni komplement i nisu neophodni za preživljavanje. Javljaju se u gotovo svim taksonima kod oko 15% vrsta. Održavanje B hromozoma objašnjava se, u parazitskom modelu, kao balans suprotnih delovanja mehanizama akumulacije i eliminacije. U heterotičnom modelu, ravnoteža se postiže zahvaljujući pozitivnim efektima malog broja B hromozoma. U ovom radu ispitivani su efekti prisustva B hromozoma na fekunditet žutogrlog miša, Apodemus flavicollis, i to kod 46 ženki sa i 28 bez B hromozoma sa 4 lokaliteta u Srbiji. Analiza uterusa pokazala je da nema značajnih razlika u prosečnom broju ožiljaka i embriona među jedinakama sa i bez B hromozoma. Prema tome, B hromozomi nemaju efekte na fekunditet ženki koje su nosioci, odnosno njihovo prisustvo ne deluje na ovu značajnu fitnes karakteristiku. Prethodni nalazi, zajedno sa našim rezultatima, podržavaju heterotički model održavanja B hromozoma kod analizirane vrste.nul

DANUBE STERLET MORPHOMETRICS AND GENETIC – GUIDELINES FOR RESTOCKING PROGRAMS

Sterlet population have experienced a decline during the 20th century throughout its range, mainly due to poorly regulated fishery, pollution, habitat fragmentation and habitat loss. Stocking programs are implemented throughout Danube River basin, so the selection of proper specimens for stocking programs should be carefully conducted. Use of both shape analysis and genetic analysis should be applied in restocking programs

Do B chromosomes affect fecundity in yellow-necked mice Apodemus flavicollis (Rodentia, Mammalia)?

The effects of the presence of B chromosomes on fecundity of the yellow-necked mouse Apodemus flavicollis were studied in 46 females without and 28 with Bs from four localities in Serbia. Uterine inspection showed that there was no significant difference in the mean number of scars and embryos between females with and those without Bs. Thus, B chromosomes do not appear to affect the fecundity of females carrying them, indicating that the presence of Bs does not affect fitness characteristics.B hromozomi su dodatni hromozomi u odnosu na standardni komplement i nisu neophodni za preživljavanje. Javljaju se u gotovo svim taksonima kod oko 15% vrsta. Održavanje B hromozoma objašnjava se, u parazitskom modelu, kao balans suprotnih delovanja mehanizama akumulacije i eliminacije. U heterotičnom modelu, ravnoteža se postiže zahvaljujući pozitivnim efektima malog broja B hromozoma. U ovom radu ispitivani su efekti prisustva B hromozoma na fekunditet žutogrlog miša, Apodemus flavicollis, i to kod 46 ženki sa i 28 bez B hromozoma sa 4 lokaliteta u Srbiji. Analiza uterusa pokazala je da nema značajnih razlika u prosečnom broju ožiljaka i embriona među jedinakama sa i bez B hromozoma. Prema tome, B hromozomi nemaju efekte na fekunditet ženki koje su nosioci, odnosno njihovo prisustvo ne deluje na ovu značajnu fitnes karakteristiku. Prethodni nalazi, zajedno sa našim rezultatima, podržavaju heterotički model održavanja B hromozoma kod analizirane vrste.nul

Distribution of B chromosomes in age categories of the yellow-necked mouse Apodemus flavicollis (Mammalia, Rodentia)

The presence of B chromosomes (Bs) is frequently found in populations of yellow-necked mouse, Apodemus flavicollis. Differences in frequencies of Bs in age categories were analyzed in 717 animals in order to clarify the mechanisms of their maintenance in populations of A. flavicollis. The absence of statistically significant differences in the frequency of Bs between six age categories indicates that the maintenance of Bs in populations can be explained by in terms of their contribution to overall genetic diversity of the species rather than by parasitic behavior.Prekobrojni hromozomi nazivaju se B hromozomi ako zadovoljavaju tri kriterijuma: nisu neophodni za preživljavanje, ne sparuju se sa hromozomima A seta i ne nasleđuju se mendelovski. B hromozomi su vrlo često prisutni u populacijama žutogrlog miša, Apodemus flavicollis. Njihovo održavanje u populacijama objašnjava se sa dva suprostavljena modela. Model označen kao parazitski tvrdi da se B hromozomi održavaju zahvaljujući mehanizmu akumulacije uprkos štetnim efektima na fitnes nosilaca. S druge strane, heterotički model sugeriše da u odsustvu akumulacije mali broj B hromozoma ima adaptivnu prednost za nosioce, dok veći broj može biti štetan. Ako B hromozomi, koji su označeni kao parazitski, redukuju fitnes kod jedinki koje su njihovi nosioci, onda je očekivano da frekvenca jedinki sa B hromozomima opada sa starošću. Analizirana je razlika u frekvenci B hromozoma u uzrasnim kategorijama kod 717 jedinki sa ciljem da se razjasne mehanizmi njihovog održavanja u populacijama A. flavicollis. Odsustvo statistički značajnih razlika u frekvenci B hromozoma između 6 uzrasnih kategorija ukazuje da se održavanje B hromozoma u populacijama ove vrste može objasniti njihovim doprinosom ukupnoj genetičkoj raznovrsnosti pre nego parazitskim ponašanjem.Projekat ministarstva br. 14301

B chromosomes and cranial variability in yellow-necked field mice (Apodemus flavicollis)

B chromosomes (Bs) are supernumerary chromosomes relative to the standard karyotype. The maintenance of Bs in the yellow-necked field mice (Apodemus flavicollis) was reconsidered by examining their effects on 3 components of cranial variability: canalization, developmental stability, and morphological integration. Bs do not disturb developmental homeostasis in their carriers. Moreover, Bs play a significant role in structuring cranial variation. We suggest that direct interactions between developmental pathways in mice without Bs might be a dominant mechanism for generating covariation of cranial traits, and integration of cranial traits in B carriers could be generated primarily by parallel variation of separate developmental pathways. Integration due to parallel variation is more predisposed to modifications by natural selection than integration caused by direct interactions, which could be beneficial to B carriers under variable environmental conditions. By contributing to the genetic variability of species possessing them, Bs provide themselves with long-term presence in populations. Therefore, the Bs of A. flavicollis should be considered as symbiotic genomic elements.Ministry of Science and Technological Development of the Republic of Serbia [173003]Journal of Mammalogy (2011), 92(2): 396-40

Cranial variability of the Serbian red fox

We used geometric morphometric techniques to examine variability in Serbian red fox (Vulpes vulpes) crania. Male crania are about 5% larger than female ones and sexual size dimorphism (SSD) was significant. Also, significant cranial shape differences were found between the sexes. Males are characterized by reduced basicranial, but broader rostral and zygomatic regions. Although a slight and significant allometric effect was detected and larger specimens are smaller in the region of basicranium, cranial sexual shape dimorphism (SShD) pattern is not influenced by SSD. As small to moderate SSD in canid species is a general characteristics of the family, additional studies are needed to determine whether basicranial reduction in males, i.e. its enlargement in females, could be an important feature in characterizing cranial SShD patterns in other Canidae members. While uniform considering size, the shape of Serbian red fox crania varies geographically, as well as depending on proportion of agricultural habitats. In comparison to those from central and eastern Serbia, specimens from the northern Serbian region Vojvodina (with higher proportions of agricultural areas) have more robust crania with shorter snouts and maxillae, larger palatine bones accompanied with anteriorly moved posterior edges of the canine alveolus and laterally expanded zygomatic arches. Encompassing mostly facial and temporal cranial regions these shape changes are probably related to diet differences, although genetic diversification cannot be excluded as a possible contributing factor.Zoologischer Anzeiger - A Journal of Comparative Zoology (2017), 267: 41-4

Two-module organization of the mandible in the yellow-necked mouse: a comparison between two different morphometric approaches

Mandibles of yellow-necked mouse (Apodemus flavicollis) were used to explore modularity. We tested a biological hypothesis that two separate modules (alveolar region and ascending ramus) can be recognized within the mandible. As a second research goal, we compared two different morphometric procedures under the assumption that methodological approaches that use either geometric or traditional morphometric techniques should give similar results. Besides confirmation of the predicted hypothesis of modularity, the application of both approaches revealed that: (i) modularity was somewhat more evident when it was analysed on the asymmetric (fluctuating asymmetry, FA) than on the symmetric (individual variation) component of variation; (ii) there is correspondence in the patterns of individual variation and FA, which indicates that integration of mandibular traits among individuals is primarily due to direct developmental interactions; and (iii) allometry does not obscure the hypothesized modularity for individual variation or for FA. In addition, traditional morphometric method allowed us to check whether allometry influenced each module to the same extent and to conclude that the ascending ramus is more heavily influenced by general size than the alveolar region. In studies of modularity, differences in methods can lead to discrepancies in the results, and therefore, some caution is required when comparing findings from different investigations. The substantial agreement between our results provides evidence that, when considering two-module organization of the mouse mandible, direct comparison among studies that use the methods applied herein is, in great part, reliable.Ministry of Education, Science and Technological Development of Serbia [173003]Journal of Evolutionary Biology (2012), 25(12): 2489–250

Discrimination of the sibling species Apodemus flavicollis and A-sylvaticus (Rodentia, Muridae)

Karyotyping and several molecular methods have allowed successful identification of two morphologically similar wide-ranging Western Palearctic species, the yellow-necked field mouse Apodemus flavicollis (Melchior, 1934) and the long-tailed wood mouse A. sylvaticus (Linnaeus, 1758), but reliable species diagnosis on the basis of morphometric characters is particularly problematic. Although they are easily morphologically distinguishable in Central and Northern Europe, this is not the case in southern parts of their distribution areas. Despite that, we have successfully discriminated A. flavicollis and A. sylvaticus from Serbia (Southern Europe) using geometric and traditional morphometric methods on a data set for ventral crania of specimens previously genotyped by the Inter Simple Sequence Repeat-PCR (ISSR-PCR). Discrimination power of applied approaches was more or less similar. The majority of our results were consistent with those obtained for specimens collected across the Czech Republic (Central Europe). Morphological differences observed herein, as well as those already reported between A. flavicollis and A. sylvaticus from the central and northern parts of their distribution areas, could be the outcome of their biology, i.e. ecological discrepancies, different assumed evolutionary scenarios considering biogeography, phylogeny, history and ontogeny. (C) 2014 Elsevier GmbH. All rights reserved.Ministry of Education, Science and Technological Development of Serbia {[}173003

Mandibular and cranial modularity in the greater horseshoe bat Rhinolophus ferrumequinum (Chiroptera: Rhinolophidae)

We report the first evaluation of mandibular and cranial modularity in the greater horseshoe bat (Rhinolophus ferrumequinum). Although some authors found no modular pattern of these morphological structures in mammals, we discovered that traits integration in R. ferrumequinum is not uniform throughout the mandible and cranium, but structured into two distinct modules. Allometry does not affect mandibular and cranial modularity in R. ferrumequinum probably as a result of the low fraction of shape variation explained by size. Observed at the static level, mandible and cranium modularity in this species could be either functional or developmental or both, but we cannot rule out a genetic nature for underlying mandibular and cranial trait interactions. Evolutionary modularity among related taxa is influenced by genetic and functional modularity. Therefore, future studies on cranial integration and modularity at multiple levels of variation may shed more light on these important features of morphological variability in bats, including R. ferrumequinum.Ministry of Education, Science and Technological Development of Serbia {[}173003