anthropology Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, society, societies, and linguistics, in both the present and past, including archaic humans. Social anthropology studies patterns of behav ...

, Sinodonty and Sundadonty are two patterns of features widely found in the

dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

s of different East Asians. These patterns were identified by anthropologist Christy G. Turner II as being within the greater "

Mongoloid Mongoloid () is an obsolete racial grouping of various peoples indigenous to large parts of Asia, the Americas, and some regions in Europe and Oceania. The term is derived from a now-disproven theory of biological race. In the past, other terms ...

dental complex". The combining forms ''

Sino- The names of China include the many contemporary and historical designations given in various languages for the East Asian country known as in Standard Chinese, a form based on the Beijing dialect of Mandarin. The English name "China" was bor ...

'' and ''Sunda-'' refer to

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

and

Sundaland Sundaland (also called Sundaica or the Sundaic region) is a biogeographical region of Southeast Asia corresponding to a larger landmass that was exposed throughout the last 2.6 million years during periods when sea levels were lower. It inc ...

, respectively, while refers to teeth.

Proto-sundadonty hypothesis

Tsunehiko Hanihara (1993) believed that the dental features of

Aboriginal Australians Aboriginal Australians are the various indigenous peoples of the Mainland Australia, Australian mainland and many of its islands, excluding the ethnically distinct people of the Torres Strait Islands. Humans first migrated to Australia (co ...

have the characteristic of high frequencies of "''evolutionarily conservative characteristics,''" which he called the " proto-sundadont" pattern, as he believed that the dental pattern of Aboriginal Australians was ancestral to that of Southeast Asians.Hanihara, Tsunehiko. (1993). Craniofacial Features of Southeast Asians and Jomonese: A Reconsideration of Their Microevolution Since the Late Pleistocene. ''Anthropological Science, 101''(1). Page 26. Retrieved March 8, 2018, fro
link to the PDF document
C.G Turner II shows with his analysis of 2016 that sundadonty is the proto-East Eurasian dental morphology and is not connected to the Australian dental morphology, rendering the term "proto-sundadont" inaccurate for the Australian dental morphology. He also shows that sinodonty is predominant in Native Americans.

Super-Sinodont

Analysis on the Sinodonty and Sundadonty of New world groups by G.R. Sott et al. (2016) shows the distinction among East Asians is not nearly as dramatic as the difference between all Asians and all New World groups. Other researchers like Stojanowski et al., 2013; Stojanowski and Johnson, (2015) suggest New World groups may be neither Sinodont nor Sundadont and in most regards, could be viewed as super-Sinodont. A clear dental morphology not only ties New World groups to Asians, particularly northeast Asians, but it also exhibits a pattern largely consistent with the Beringian Standstill model (BSM) based on a Sinodont source population.

Mongoloid dental complex

Turner defined the Sinodont and Sundadont dental complexes in contrast to a broader Mongoloid dental complex. Hanihara defined the Mongoloid dental complex in 1966. In 1984, Turner separated the Mongoloid dental complex into the Sinodont and Sundadont dental complexes. Ryuta Hamada, Shintaro Kondo and Eizo Wakatsuki (1997) said, on the basis of dental traits, that

s are separated into sinodonts and sundadonts, which is supported by Christy G. Turner II (1989).Hamada, Ryuta, Kondo, Shintaro & Wakatsuki, Eizo. (1997). Odontometrical Analysis of Filipino Dentition. ''The Journal of Showa University Dental Society, 17''. Page 197. Retrieved March 8, 2018, fro
link to the PDF document

Sundadont

Turner found the Sundadont pattern in the skeletal remains of

Jōmon people The Jōmon (縄文) were a prehistoric hunter-gatherer culture that inhabited the Japanese archipelago approximately between 14,000 BC and 300 BC. Both genetically and culturally, the Jōmon are among the earliest known ancestors of the modern ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, and in living populations of

Taiwanese indigenous peoples Taiwanese indigenous peoples, formerly called Taiwanese aborigines, are the indigenous peoples of Taiwan, with the nationally recognized subgroups numbering about 600,303 or 3% of the Geography of Taiwan, island's population. This total is incr ...

Filipinos Filipinos () are citizens or people identified with the country of the Philippines. Filipinos come from various Austronesian peoples, all typically speaking Filipino language, Filipino, Philippine English, English, or other Philippine language ...

Indonesians Indonesians (Indonesian language, Indonesian: ''orang Indonesia'') are citizens or people who are identified with the country of Indonesia, regardless of their ethnic or religious background. There are more than Ethnic groups in Indonesia, 1,300 ...

, Borneans, and Malays. In 1996, Rebecca Haydenblit of the Hominid Evolutionary Biology Research Group at

Cambridge University The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

did a study on the dentition of four

Pre-Columbian era In the history of the Americas, the pre-Columbian era, also known as the pre-contact era, or as the pre-Cabraline era specifically in Brazil, spans from the initial peopling of the Americas in the Upper Paleolithic to the onset of European col ...

Mesoamerica Mesoamerica is a historical region and cultural area that begins in the southern part of North America and extends to the Pacific coast of Central America, thus comprising the lands of central and southern Mexico, all of Belize, Guatemala, El S ...

n populations and compared their data to other Eastern Eurasian populations. She found that " Tlatilco", " Cuicuilco", "

Monte Albán Monte Albán is a large pre-Columbian archaeological site in the Santa Cruz Xoxocotlán Municipality in the southern Mexico, Mexican state of Oaxaca (17.043° N, 96.767°W). The site is located on a low mountainous range rising above the plain i ...

" and " Cholula" populations followed an overall Sundadont dental pattern "characteristic of Southeast Asia" rather than a Sinodont dental pattern "characteristic of Northeast Asia". According to a 2016 study, Sundadonty is characterized by an early generalized pattern with simple crown and root traits.

Sinodont

Turner found the Sinodont pattern in the

Han Chinese The Han Chinese, alternatively the Han people, are an East Asian people, East Asian ethnic group native to Greater China. With a global population of over 1.4 billion, the Han Chinese are the list of contemporary ethnic groups, world's la ...

, in the inhabitants of

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

and eastern

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

, in the Native Americans, and in the

Yayoi people The were an ancient people that immigrated to the Japanese archipelago during the Yayoi period (300 BC–300 AD) and are characterized by the existence of Yayoi material culture. Some argue for an earlier start of the Yayoi period, between 1 ...

of Japan. Sinodonty is a particular pattern of

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

characterized by the following features: * The upper first

incisors Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

and upper second incisors are shovel-shaped, and they are "not aligned with the other teeth".Kimura, R. et al. (2009). A Common Variation in EDAR Is a Genetic Determinant of Shovel-Shaped Incisors. In

American Journal of Human Genetics The ''American Journal of Human Genetics'' is a monthly peer-reviewed scientific journal in the field of human genetics. It was established in 1948 by the American Society of Human Genetics and covers all aspects of heredity in humans, including ...

, 85(4). Page 528. Retrieved December 24, 2016, fro
link
* The upper first

premolar The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

has one root, and the lower first molar in Sinodonts has three roots (3RM1).Scott, R.G. (1997). Encyclopedia of Human Biology. Second Edition. Volume 3. Pages 175-190. Retrieved December 14, 2016, fro
link

Associated traits

The EDAR gene causes the Sinodont tooth pattern, and also affects hair texture, jaw morphology, and perhaps the nutritional profile of

breast milk Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by the mammary glands in the breasts of women. Breast milk is the primary source of nutrition for newborn infants, comprising fats, proteins, carbohydrates, and a var ...

Applicability

In the 1990s, Turner's dental morphological traits were frequently mentioned as one of three new tools for studying origins and migrations of human populations. The other two were linguistic methods such as

Joseph Greenberg Joseph Harold Greenberg (May 28, 1915 – May 7, 2001) was an American linguist, known mainly for his work concerning linguistic typology and the genetic classification of languages. Life Early life and education Joseph Greenberg was born on M ...

's mass comparison of vocabulary or Johanna Nichols's statistical study of language typology and its evolution, and genetic studies pioneered by

Cavalli-Sforza Luigi Luca Cavalli-Sforza (; 25 January 1922 – 31 August 2018) was an Italian geneticist. He was a population geneticist who taught at the University of Parma, the University of Pavia and then at Stanford University. Works Schooling and p ...

. Today, the largest number of references to Turner's work are from discussions of the origin of Paleo-Amerindians and modern Native Americans, including the

Kennewick Man Kennewick Man or Ancient One was a Native American man who lived during the early Holocene, whose skeletal remains were found in 1996 washed out on a bank of the Columbia River near Kennewick, Washington. Radiocarbon tests show the man lived a ...

controversy. Turner found that the dental remains of both ancient and modern Amerindians are more similar to each other than they are to dental complexes from other continents, but that the Sinodont patterns of the Paleo-Amerindians identify their ancestral homeland as north-east Asia. Some later studies^{hich?/sup> have questioned this and found Sundadont features in some American peoples.

A study done by Stojonowski et al in 2015 found a "significant interobserver error" in the earlier studies and their statistical analysis of matched wear and morphology scores suggests trait downgrading for some traits.

See also

* Ainu people

The Ainu are an Indigenous peoples, indigenous ethnic group who reside in northern Japan and southeastern Russia, including Hokkaido and the Tōhoku region of Honshu, as well as the land surrounding the Sea of Okhotsk, such as Sakhalin, the Ku ...

* Austronesian peoples

The Austronesian people, sometimes referred to as Austronesian-speaking peoples, are a large group of peoples who have settled in Taiwan, maritime Southeast Asia, parts of mainland Southeast Asia, Micronesia, coastal New Guinea, Island Melan ...

* Malay race
* Mongoloid

Mongoloid () is an obsolete racial grouping of various peoples indigenous to large parts of Asia, the Americas, and some regions in Europe and Oceania. The term is derived from a now-disproven theory of biological race. In the past, other terms ...

* Odontometrics
* Shovel-shaped incisors

Shovel-shaped incisors (or, more simply, shovel incisors) are incisors whose Glossary of dentistry, lingual surfaces are scooped as a consequence of lingual marginal ridges, Crown (tooth), crown curvature, or Basal (anatomy), basal Tubercle (ana ...

References

{{reflist

Pseudoscience
Stereotypes of East Asian people
Dentition types
Human mouth anatomy}