İNSAN DENTAL VARYASYONUNDA EVRİMSEL SÜREÇLER: NÖTRALİZM VE ADAPTASYONUN ROLÜ

Abstract

Popülasyonlar arasındaki biyolojik ilişkileri ve göç hareketlerini belirlemek için dişin morfolojik özelliklerini kullanan antropolojik çalışmalar, bu özelliklerin nötral evrimsel süreçlerle oluştuğu varsayımıyla yola çıkmaktadır. Nötral evrim yaklaşımına göre, gözlemlenen varyasyonlar, genetik sürüklenme ve kurucu etkisi gibi şansa bağlı olaylar tarafından şekillenmiştir. Nötral yaklaşımın zıttı olarak kabul edilen adaptif yaklaşıma göre ise, diş özellikleri doğal seçilim baskısı sebebiyle çevre şartlarına uyarlanmış adaptif özelliklerdir. Adaptif yaklaşım, diş özelliklerinin tesadüfi olarak oluşmadıklarını, bireye fonksiyonel avantaj sağladıkları için pozitif seçilime uğradıklarını ileri sürmektedir. İnsan dişinde gözlenen morfolojik varyasyonun çevresel baskılarla mı yoksa nötral bir şekilde mi evrimleştiğinin aydınlatılması önem arz etmektedir. Bu varyasyonun nötral olmadığı ve çevresel baskılarla şekillendiği varsayımı doğru ise, bu çalışmalar popülasyonlar arasındaki genetik ilişkiler yerine diyet ve iklim gibi etkileri yansıtacağından yanıltıcı sonuçlar verebilir. Bunun sonucu olarak, antropolojide geleneksel olarak kullanılan diş özelliklerinin biyolojik ilişkileri belirmede güvenilirliği tehlikeye girecektir. Bu makalede, adaptif ve nötral evrim yaklaşımları ile ilgili literatür diş özellikleri bağlamında değerlendirilmiştir.

Keywords

• Metrik olmayan diş özellikleri
• Nötral evrim
• Biyolojik uzaklık
• Adaptasyon
• Doğal seçilim

EVOLUTIONARY PROCESSES IN HUMAN DENTAL VARIATION: THE ROLE OF NEUTRALISM AND ADAPTATION

Abstract

Anthropological studies that use dental morphological traits to determine biological relationships and population movements rely on the assumption that these traits are formed by neutral evolutionary processes. According to the neutral evolutionary approach, observed variations are shaped by random events such as genetic drift and founder effects. In contrast to the neutral approach, the adaptive approach assumes that dental traits are traits adapted to environmental conditions due to natural selection pressure. The adaptive approach argues that dental traits do not occur by chance, but are subject to positive selection because they confer a functional advantage to the individual. It is important to clarify whether the morphological variation observed in human teeth is due to environmental pressures or whether it evolved neutrally. If the assumption that this variation is not neutral and is shaped by environmental pressures is correct, these studies may yield misleading results by reflecting influences such as diet and climate rather than genetic relationships between populations. Consequently, the reliability of dental traits traditionally used in anthropology to determine biological relationships would be compromised. In this article, the literature on adaptive and neutral evolutionary approaches in the context of dental traits is reviewed.

Keywords

• Dental nonmetric traits
• Neutral evolution
• Biodistance
• Adaptation
• Natural selection

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