Expression of the entoconulid (sixth cusp) on mandibular molar teeth of an Australian aboriginal population
✍ Scribed by Dr. Grant Townsend; Hiroyuki Yamada; Patricia Smith
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 803 KB
- Volume
- 82
- Category
- Article
- ISSN
- 0002-9483
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✦ Synopsis
The expression and genetic basis of the entoconulid (sixth cusp) on mandibular molars were examined in a geographically isolated group of aboriginals from Yuendumu in the Northern Territory of Australia. Four grades of trait expression, ranging from trace to small, medium, and large cusps, were defined on dental casts of 399 subjects. Frequencies of occurrence were among the highest reported in human populations. Approximately 80% of dm2s showed the trait, whereas frequencies in the permanent dentition ranged from around 50% on M2 to 70% on M1 and 80% on M3. The degree of expression increased distally along the molar series, with only 3% of dm2s showing large cusps compared with 25% of M3s. Fluctuating asymmetry was highest for M2 and lowest for dm2. No strong evidence for sexual dimorphism