The Skull Shape Analysis of Wistar Albino Rats: A Geometric Morphometric Study

Abstract

The aim of the study was to evaluate the skull shape of Wistar albino rats using the geometric morphometry method. For this purpose, a total of 52 adult rat skulls, 31 female and 21 male, were evaluated. Skulls were photographed from equal distances in dorsal and ventral directions. 13 and 18 landmarks were marked in dorsal and ventral images, respectively. Percentage variation values of principal components were calculated by performing principal components analysis in the MorphoJ program. Average shape graphs showing the positive and negative boundaries of the first three principal components were obtained. It was defined that scatter plot showing the degree of grouping of male and female rats according to the first and second principal components. The study also examined the allometric effect with regression. Discriminant function analysis was performed to examine gender dimorphism. As a result of the study, it was determined that the most significant shape change was in the zygomatic arc and palate regions according to individuals, while it was also in the neurocranium according to gender. We believe that the study will contribute to anatomy, biology and archeology studies on the shape of the skull.

Keywords

• Gender
• Geometric morphometry
• Rat
• Shape
• Skull

Wistar Albino Ratların Kafatası Şekil Analizi: Bir Geometrik Morfometrik Çalışma

Abstract

Çalışmada Wistar albino ratlarda kafatası şeklinin geometrik morfometri yöntemi ile değerlendirilmesi amaçlandı. Bu amaçla erişkin 31 dişi, 21 erkek olmak üzere toplam 52 adet rat kafatası değerlendirildi. Kafatasları dorsal ve ventral yönde eşit uzaklıktan fotoğraflandı. Dorsal görüntülerde 13, ventral görüntülerde 18 landmark işaretlendi. MorphoJ programında temel bileşenler analizi yapılarak temel bileşenlerin yüzde varyasyon değerleri hesaplandı ve ilk üç principal componentin pozitif negatif sınırlarını gösteren ortalama şekil grafikleri elde edildi. Erkek ve dişi ratların birinci ve ikinci temel bileşene göre gruplanma derecelerini gösteren dağılım grafiği tanımlandı. Çalışmada ayrıca regresyon ile allometrik etkiye bakıldı. Cinsiyet farkını incelemek için discriminant (ayırma) analizi yapıldı. Çalışma sonucunda wistar rat kafatasında bireyler arasında en belirgin şekilsel değişimin arcus zygomaticus (elmacık kemeri) ve damak bölgesinde olduğu, cinsiyete göre ise neurocranium da olduğu belirlendi. Çalışmanın, kafatasında cinsiyet farklılığı ile ilgili anatomi, biyoloji ve arkeoloji çalışmalarına katkı sağlayacağı kanaatindeyiz.

Keywords

• Cinsiyet
• Geometrik morfometri
• Kafatası
• Rat
• Şekil

References

1. Abdel-Rahman, E.H., Taylor, P.J., Contrafatto, G., Lamb, J.M., Bloomer, P., & Chimimba, C.T. (2009). Geometric craniometric analysis of sexual dimorphism and ontogenetic variation: A case study based on two geographically disparate species, Aethomys ineptus from southern Africa and Arvicanthis niloticus from Sudan (Rodentia: Muridae). Mammalian Biology, 74 (5), 361-373.
2. Clause, B.T. (1998). The Wistar Institute Archives: Rats (Not Mice) and History. Mendel Newsletter, 7, 2-7.
3. Çalışır, M., Üstündağ, Y., & Yılmaz, O. (2023). A study on head measurements in different labatory rat strains. Turkish Journal of Hip Surgery, 3(1), 189-195. https://doi.org/10.5505/TJHS.2023.09797
4. Dayan, M.O., Demircioğlu, İ., Koçyiğit, A., Güzel, B.C., & Karaavci, F.A. (2023). Morphometric analysis of the skull of Hamdani sheep via Three-Dimensional modelling. Anatomia Histologia Embryologia, 52, 215–222. https://doi.org/10.1111/ahe.12873
5. Demircioğlu, İ., Demiraslan, Y., Gürbüz, İ., & Dayan, M.O. (2021). Geometric morphometric analysis of skull and mandible in Awassi ewe and ram. Kafkas Universitesi Veteriner Fakultesi Dergisi, 27, 1, 43–49. https://doi.org/10.9775/kvfd.2020.24714
6. Gannon, W.L., & Rácz, G.R. (2006). Character displacement and ecomorphological analysis of two long-eared myotis (M. aurıculus and M. evotis). Journal of Mammalogy, 87 (1), 171-179. https://doi.org/10.1644/05-mamm-a-140r1.1
7. Gündemir, O., Duro, S., Szara, T., Koungoulos, L., Jashari, T., Demircioğlu, İ., Hadziomerovic, N., Ilieski, V., & Melnyk, O. (2023a). Skull variation in different breeds sheep from Balkan countries. Annals of Anatomy, 249, 152083. https://doi.org/10.1016/j.aanat.2023.152083
8. Gündemir, O., Koungoulos, L., Szara, T., Duro, S., Spataru, M.C., Michaud, M., & Onar, V. (2023b). Cranial morphology of Balkan and West Asian livestock guardian dogs. Annals of Anatomy, 243, 951-959. https://doi.org/10.1111/joa.13929

9. Gürbüz, İ., Demiraslan, Y., Karaavcı, F.A., Yılmaz, O., & Demircioğlu, İ. (2022). Geometric morphometric analysis on the skull of the Red Fox Vulpes vulpes. Harran Üniversitesi Veteriner Fakültesi Dergisi, 11, 1, 1–7. https://doi.org/10.31196/huvfd.1012563
10. Herrel, A., Fabre, A.C., Hugot, J.P., Keovichit, K., Adriaens, D., Brabant, L., Van Hoorebeke, L., & Cornette, R. (2012). Ontogeny of the cranial system in Laonastes aenigmamus. Journal of Anatomy, 221 (2), 128-137. https://doi.org/10.1111/j.1469-7580.2012.01519.x
11. Hughes, P.C., Tanner, J.M., & Williams, J.P. (1978). A longitudinal radiographic study of the growth of the rat skull. Journal of Anatomy, 127, 83-91.
12. Karaavcı, F.A., Demiraslan, Y., Demircioğlu, İ., Gürbüz, İ., & Özgel, Ö. (2024). Orbital shape in sheep and goats with sex and breed factors. Anatomia Histologia Embryologia, 53:e12971. https://doi.org/10.1111/ahe.12971
13. Klingenberg, C.P. (2011). MorphoJ: an integrated software package for geometric Morphometrics. Molecular Ecology Resources, 11, 353–357. https://doi.org/10.1111/j.1755-0998.2010.02924.x
14. Leblanc, M., Festa-Bianchet, M., & Jorgenson, J.T. (2001). Sexual size dimorphism in bighorn sheep (Ovis canadensis): Effects of population density. Canadian Journal of Zoology, 79, 1661-1670. https://doi.org/10.1139/cjz-79-9-1661
15. Lieberman, D.E., Ross, C.F., & Ravosa, M.J. (2000). The primate cranial base: ontogeny, function, and integration. American Journal of Physical Anthropology, 113 (S31), 117–169. https://doi.org/10.1002/1096-8644(2000)43:31+<117::AID-AJPA5>3.0.CO;2-I
16. Matina, C., Kalcounis, R., Radmila, P., Jessica, R.B., Catherine, C., Matthew, M.M., John, T.W., Olav, R., David, O.R., & Jannet, P.C. (2010). Differences in ultrasonic vocalizations between wild and laboratory California mice (Peromyscus californicus). PlosOne, 5(4), e9705. https://doi.org/10.1371/journal.pone.0009705.
17. Mitteroecker, P., & Gunz, P. (2009). Advances in geometric morphometrics, Evolutionary Biology, 36, 235-47. Musser, G.G., & Carleton, M.D. (2005). Superfamily Muroidea. In: Wilson DE, Reeder DM, edt. Mammal species of the world. The Johns Hopkins University Press, 894-1531.
18. Odigiea, E.A., Ekeolu, O.K., Asemota, D.O., Uwagie-Ero, E.A., Aighewi, I.T., Ighedosa, S.U., Usifoh, S.F., Olugasa, B.O., Asemota, O., & Fagboya, T.E. (2018). Comparative non-metric and morphometric analyses of rats at residential halls of the University of Benin campus, Nigeria. Journal of Infection Public Health, 11 (3), 412-417. http://dx.doi.org/10.1016/j.jiph.2017.09.003
19. Olude, M.A., Olopade, J.O., Fatola, I.O., & Onwuka, S.K. (2009). Some aspects of the neurocraniometry of the African giant rat (Cricetomys gambianus Waterhouse). Folia Morphologica, 68(4), 224-227.
20. Özcan, S., & Demiraslan, Y. (2022). Apparatus locomotorius. In: Demiraslan Y, Dayan MO eds. Veteriner Sistematik Anatomi. Nobel Tıp Kitabevleri, 15-36.
21. Reichs, K.J., & Bass, W.M. (1998). Forensic Osteology, Advances in the identification of human remains, Chapter 8: Observational and metric analysis of sex in the skeleton by D.L. France; Charles C. Thomas Publisher, Ltd., Illinois, USA. 163-8
22. Rohlf, F.J. (2018). TpsDig Version 2.31. Ecology & Evolution, SUNY at Stone Brook, USA. http://life.bio.sunysb.edu/morph/index.html
23. Rohlf, F.J. (2019). TpsUtil program Version 1.79. Ecology & Evolution, State University of New York, Stony Brook, NY
24. Samuel, O.M., Parés-Casanova, P.M., Nwaogu, I.C., & Olopade, J.O. (2015). Geometric morphometrics of the skull of two African rodents, Thryonomys swinderianus and Cricetomys gambianus. Annals of Experimental Biology, 3 (2), 21-30
25. Sharp, A.C., Dutel, H., Watson, P.J., Gröning, F., Crumpton, N., Fagan, M.J., & Evans, S.E. (2023). Assessment of the mechanical role of cranial sutures in the mammalian skull: Computational biomechanical modelling of the rat skull. Journal of Morphology, 284, e21555. http://dx.doi.org/10.1002/jmor.21555
26. Slice, D.E. (2007). Geometric morphometrics. Annual Review of Anthropology, 36, 261–281. https://doi.org/10.1146/annurev.anthro.34.081804.120613
27. Slice, D.E., Bookstein, F.L., Marcus, L.F., & Rohlf, F.J. (2010). A glossary for geometric morphometrics. [Erişim tarihi: 20.10.2023].
28. Szara, T., Duro, S., Gündemir, O., & Demircioğlu, İ. (2022). Sex Determination in Japanese Quails Coturnix japonica Using Geometric Morphometrics of the Skull. Animals, 12, 302, 1-10. https://doi.org/10.3390/ani12030302
29. Villalobos-Leiva, A., & Benitez, H.A. (2020). Morfometría Geométrica y sus Nuevas Aplicaciones en Ecología y Biología Evolutiva: Parte 2. International Journal of Morphology, 38, 1818–1836. http://dx.doi.org/10.4067/S0717-95022020000601818
30. Zelditch, M.L., Swiderski, D.L., & Sheets, H.D. (2012). Geometric Morphometrics for Biologists. A Primer, Elsevier, Amsterdam, The Netherlands.