Ten millennia of hepatitis B virus evolution

[Figure: see text].

Discrete morphological variants of human cervical vertebrae: Exploring pattern of distribution and biological significance

Studies on discrete traits of the human cervical vertebrae, appearing at certain intervals during the last century, posed some questions regarding evolutionary processes that human cervical spine underwent during phylogenesis. To address questions of significance of these morphological traits we need first a good knowledge of the extent of their variation in modern humans. The aim of the current work was to integrate available data on the occurrence of various non-metric traits in the human cervical spine and search for the pattern of their distribution on intra- and inter-population levels. The study was based on data from five osteological samples from North America (Terry and Grant collections) and Russia (mid 20th c. and 18th c.); and data taken from literature. Traits were categorized into rare (<3%), low frequency (up to 10%), often encountered (10-30%) and characteristic for modern humans (>50% on average). Several traits showed mild to strong association with each other indicating interrelation between various spine characteristics. Of the traits analyzed, the following had consistent pattern of sex-related variability: complete dorsal ponticle, bifid spinous processes and cervical ribs; and ancestry-related variability: dorsal ponticle and bifid spinous processes. Each ancestry group (European, African, Asian and North American) had its specifics regarding the latter two traits which might be related to genetic isolation. Most of the traits, however, showed relatively similar pattern of distribution among various populations, including the pattern of within-spine variability. This suggests a common intraspecific pattern and a possible link to some fundamental characteristics of the human vertebral column.

[Osteometric determination of ordinal localization, sex, and body length in man from skeletonized lumbar vertebrae]

Dimensional characteristics of lumbar vertebrae (L1-L5) were obtained by examination of three osteologic collections containing a total of 304 male and 181 female vertebrae. The multimetric (14 parameters) discriminative analysis has demonstrated that the highest accuracy of ordinal localization based on the general diagnostic model (L1-L5) was obtained for L5 (93.76%) and the lowest one for L2 (56.45%). Correction of the results using several discrimination models improved the accuracy of classification to 76.65% (L1), 81.61% (L2), 79.82% (L3), and 81.99% (L4). Diagnosis of gender identity of isolated lumbar vertebrae by multimetric discriminative analysis proved to be possible in 87.7-88.8% of the cases; this figure amounted to 93.8% if the totality of these vertebrae was included in the analysis. The accuracy of body length measurements using multiple regression equations was estimated at +/- 6.22-6.45 cm for individual vertebrae and +/- 0.62 cm based on the complete set of them. In all these cases, sex and age of the subjects should be taken into consideration. It is concluded that the proposed methods can be used in forensic medical practice for the identification of skeletonized bone remains.