Exploring directional and fluctuating asymmetry in the human palate during growth

open24siObjectives: Palate morphology is constantly changing throughout an individual's lifespan, yet its asymmetry during growth is still little understood. In this research, we focus on the study of palate morphology by using 3D geometric morphometric approaches to observe changes at different stages of life, and to quantify the impact of directional and fluctuating asymmetry on different areas at different growth stages. Materials and Methods: The sample consists of 183 individuals (1–72 years) from two identified human skeletal collections of 19th and early 20th Century Italian contexts. A 3D-template of 41 (semi)landmarks was applied on digital palate models to observe morphological variation during growth. Results: Asymmetrical components of the morphological structure appears multidirectional on the entire palate surface in individuals <2 years old and become oriented (opposite bilateral direction) between 2 and 6 years of age. Specifically, directional asymmetry differentially impacts palate morphology at different stages of growth. Both the anterior and posterior palate are affected by mild alterations in the first year of life, while between 2 and 6 years asymmetry is segregated in the anterior area, and moderate asymmetry affects the entire palatal surface up to 12 years of age. Our results show that stability of the masticatory system seems to be reached around 13–35 years first by females and then males. From 36 years on both sexes show similar asymmetry on the anterior area. Regarding fluctuating asymmetry, inter-individual variability is mostly visible up to 12 years of age, after which only directional trends can be clearly observed at a group level. Discussion: Morphological structure appears instable during the first year of life and acquires an opposite asymmetric bilateral direction between 2 and 6 years of age. This condition has been also documented in adults; when paired with vertical alteration, anterior/posterior asymmetry seems to characterize palate morphology, which is probably due to mechanical factors during the lifespan. Fluctuating asymmetry is predominant in the first period of life due to a plausible relationship with the strength of morphological instability of the masticatory system. Directional asymmetry, on the other hand, shows that the patterning of group-level morphological change might be explained as a functional response to differential inputs (physiological forces, nutritive and non-nutritive habits, para-masticatory activity as well as the development of speech) in different growth stages. This research has implications with respect to medical and evolutionary fields. In medicine, palate morphology should be considered when planning orthodontic and surgical procedures as it could affect the outcome. As far as an evolutionary perspective is concerned the dominance of directional asymmetries in the masticatory system could provide information on dietary and cultural habits as well as pathological conditions in our ancestors.embargoed_20220511Oxilia G.; Menghi Sartorio J.C.; Bortolini E.; Zampirolo G.; Papini A.; Boggioni M.; Martini S.; Marciani F.; Arrighi S.; Figus C.; Marciani G.; Romandini M.; Silvestrini S.; Pedrosi M.E.; Mori T.; Riga A.; Kullmer O.; Sarig R.; Fiorenza L.; Giganti M.; Sorrentino R.; Belcastro M.G.; Cecchi J.M.; Benazzi S.Oxilia G.; Menghi Sartorio J.C.; Bortolini E.; Zampirolo G.; Papini A.; Boggioni M.; Martini S.; Marciani F.; Arrighi S.; Figus C.; Marciani G.; Romandini M.; Silvestrini S.; Pedrosi M.E.; Mori T.; Riga A.; Kullmer O.; Sarig R.; Fiorenza L.; Giganti M.; Sorrentino R.; Belcastro M.G.; Cecchi J.M.; Benazzi S

LEBBRA E TUBERCOLOSI: ANALISI DI CASI PROVENIENTI DALLE NECROPOLI ALTOMEDIOEVALI DI VICENNE E MORRIONE (CAMPOCHIARO, MOLISE)

Dall\u2019esame paleopatologico degli scheletri provenienti dalle necropoli altomedievali (VI-VII sec.AD) di Vicenne (167 sepolture) e Morrione (234 sepolture) (Campochiaro, CB), necropoli rinvenute nella stessa area geografica a meno di 1 km di distanza l\u2019una dall\u2019altra, \ue8 emerso che tre scheletri presentano lesioni presumibilmente riconducibili a tubercolosi e sei lesioni riconducibili a lebbra (cfr. Belcastro et al., 2005; Rubini e Zaio, 2009). La presenza di entrambe le malattie nei campioni presi in esame \ue8 particolarmente interessante in relazione agli aspetti di ordine immunologico che interessano lebbra e tubercolosi. \uc8 noto che Mycobacterium leprae e Mycobacterium tuberculosis, agenti patogeni rispettivamente di lebbra e tubercolosi, sono legati da un rapporto di immunit\ue0 specifica acquisita, ovvero l\u2019esposizione dei soggetti a M. tuberculosis renderebbe immuni, o parzialmente immuni, all\u2019infezione da M. leprae; per questo motivo nel corso della storia la loro presenza tende ad escludersi reciprocamente, andando incontro ad un lento declino della lebbra a favore dell\u2019affermazione della tubercolosi negli ultimi secoli (Manchester, 1991). Pertanto l\u2019incidenza di lebbra e tubercolosi nelle due aree di inumazione pu\uf2 fornire importanti indicazioni rispetto alle modalit\ue0 e ai tempi di utilizzo delle aree sepolcrali. Per la rilevazione delle lesioni ossee della tubercolosi, lesioni molto variabili a seconda dell\u2019et\ue0, ci si \ue8 avvalsi di una scheda basata sui dati ottenuti dallo studio di un campione italiano moderno identificato (XIX-XX sec.) di cui sono noti sesso, et\ue0 e causa di morte. La collezione comprende 372 individui, di cui 68 (35 maschi e 33 femmine) morti di tubercolosi (collezione custodita presso il Museo di Antropologia, Universit\ue0 di Bologna)