Christopher W. Schmidt - University of Indianapolis Archeology ...

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variation within populations cannot be demonstrated with samples of a modest size, particularly once they are subdivided by sex and age. Rhine undoubtedly chose to group males and females together and to ignore age because the sample was too small to split up. In another study, Angel and Kelley (1990) focused solely on two non-metric traits as ancestral indicators: inversion of the posterior border of the mandibular ramus and eversion of the gonia. They looked at a total of 376 females and 406 males spanning 5 generations. Their sample consisted of a number of individuals from the Terry collection, forensic cases, two 19th century African American cemeteries, and Plains Indians. Angel and Kelley determined the degree of inversion and gonial flare by scoring each trait on a four-point scale (absent, slight, marked, and extremely marked). However, they did not describe these categories or the boundaries between them, leading to possible confusion in scoring these traits if used by other researchers. Inversion of the ramus was found to vary between the populations studied. European Americans had inversion present 30% of the time, whereas in African Americans, inversion was observed in 95% of the individuals examined. The Native American population fell between the European Americans and African Americans, with inversion present 44.5% of the time. There is a significant difference in the amount of ramus inversion between European and African Americans. However, the Native American population is not significantly different from the European American population. The results for gonial eversion were more homogenous and do not appear to have produced any statistically significant differences. European Americans exhibited eversion 77.1% of the time, while African Americans displayed eversion in 89.1% of the cases. The smallest percentage of gonial eversion was found in Native Americans, with 63.8% of the sample 17
displaying the trait. In the entire sample, 27.1% of the females and 11.4% of the males lacked gonial eversion. Despite the demonstrated differences in ramus inversion, the question remains as to why these differences exist. Angel and Kelley noted that there are several muscles and ligaments that attach at these locations, but they do not delve far into how these soft tissues may account for the ancestral differences seen in the posterior mandible. In 2001, Berg performed a study on the mandibles of European Americans, Africans (Nubians), and South East Asians. The European American sample was composed of United States service personnel. However, this sample was so small that Berg included the European American data published in Rhine (1990) and Angel and Kelley (1990). Similarly, his African sample also includes published data from Angel and Kelley (1990). Only males and “probable” males were analyzed due to the small sample size of females. Berg analyzed seven traits: the shape of the chin, the lower border of the mandible, the shape of the ascending ramus, the profile of the ascending ramus, gonial flare, mandibular torus, and inversion of the posterior edge of the ramus (see Table 2.4). Exact frequencies are only provided for a few of the traits. Berg found that a bilobate chin type was most common in European Americans, while both SE Asians and Africans had a blunt chin. Previous studies have shown that an undulating mandibular border is the most common form in European Americans (Rhine, 1990). However, in Berg’s sample all three ancestral groups possess an undulating mandibular border at similar rates. An undulating mandibular border is the most common form in all three populations, however, the rocker jaw is also commonly found in the SE Asian and African groups. Using a composite of Rhine’s data and his own, Berg noted that European Americans were most likely to have a pinched ascending ramus. However, Berg’s European American sample displayed a 18
Page 1 and 2: Determination of Ancestry from Disc
Page 3 and 4: DEDICATION I would like to dedicate
Page 5 and 6: ABSTRACT In the field of forensic a
Page 7 and 8: TABLE OF CONTENTS Signature Page .
Page 9 and 10: a,b,c) were the first to show that
Page 11 and 12: 1998, p. 102): Most non-metric trai
Page 13 and 14: Sex. A number of researchers have f
Page 15 and 16: statistics. Being discontinuous in
Page 17 and 18: CHAPTER 2: BACKGROUND The most reli
Page 19 and 20: Murphy (1957) performed another non
Page 21 and 22: younger and older adults. Modern St
Page 23: TABLE 2.3. Rhine’s (1990) Non-Met
Page 27 and 28: European Americans and Africans. Be
Page 29 and 30: TABLE 2.5. Populations Analyzed for
Page 31 and 32: mandibles. Thirty-two percent of th
Page 33 and 34: Sawyer and colleagues (1998) conduc
Page 35 and 36: 1990; Manjunath, 2003), while other
Page 37 and 38: performed using chi-squared analysi
Page 39 and 40: archeological setting. On the other
Page 41 and 42: collections are usually prehistoric
Page 43 and 44: TABLE 3.3. Age Distribution for the
Page 45 and 46: The African American males have an
Page 47 and 48: “2” is assigned when a moderate
Page 49 and 50: Square: this category includes thos
Page 51 and 52: continuously varying independent va
Page 53 and 54: Descriptive Statistics CHAPTER 4: R
Page 55 and 56: TABLE 4.4. Location of Inversion Fr
Page 57 and 58: TABLE 4.10. Mandibular Border Form
Page 59 and 60: TABLE 4.16. Muscle Attachment Sites
Page 61 and 62: TABLE 4.22. Accessory Mandibular Fo
Page 63 and 64: TABLE 4.28. Chin Shape Frequencies.
Page 65 and 66: TABLE 4.34. Position of the Mental
Page 67 and 68: TABLE 4.37. Male and Female Trait F
Page 69 and 70: Ordinal Regression on All Populatio
Page 71 and 72: trait is on the border (p = 0.051)
Page 73 and 74: TABLE 4.44. Ordinal Regression Para
Page 75 and 76:
the dependent variables. Age is the
Page 77 and 78:
ANCOVA output for mandibular length
Page 79 and 80:
The ANCOVA results show that ancest
Page 81 and 82:
African Americans (96%). From these
Page 83 and 84:
with Rhine (1990), 69% of the Europ
Page 85 and 86:
(Giles, 1964). In fact, Hunter and
Page 87 and 88:
female sample displays robust muscl
Page 89 and 90:
mandibular corpus increases in leng
Page 91 and 92:
have the largest bicondylar breadth
Page 93 and 94:
displays predominately slight evers
Page 95 and 96:
African American vs. Native African
Page 97 and 98:
eadth. As expected, males have a wi
Page 99 and 100:
accessory mandibular foramen, chin
Page 101 and 102:
displayed by Native Africans includ
Page 103 and 104:
determination of ancestry. The numb
Page 105 and 106:
LITERATURE CITED Akabori K (1934) C
Page 107 and 108:
Enlow DH, Bianco HJ, Eklund S (1976
Page 109 and 110:
Lundy, JK (1980) The mylohyoid brid
Page 111 and 112:
Rosing FW (1984) Discreta of the hu
Page 113:
Zivanovic S (1970) Some morphologic
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Christopher W. Schmidt - University of Indianapolis Archeology ...

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