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

Öz

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.

Anahtar Kelimeler

• Gender
• Geometric morphometry
• Rat
• Shape
• Skull

Wistar Albino Ratların Kafatası Şekil Analizi: Bir Geometrik Morfometrik Çalışma

Öz

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.

Anahtar Kelimeler

• Cinsiyet
• Geometrik morfometri
• Kafatası
• Rat
• Şekil

Kaynakça

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