Skeletal evidence of health and disease in pre-contact Alaskan Eskimos and Aleuts

There have been relatively few paleopathological studies of arctic populations to date, compared to other regions of North America. Studies aimed at elucidating patterns of health and disease in arctic peoples prior to contact and assessing inter- and intraregional differences in disease patterns have been particularly few. In the present study, five pre-contact skeletal samples (N = 193), representing 4 Eskimo populations from northern coastal Alaska and 1 Aleut population from the eastern Aleutian Islands, were examined macroscopically for the following indicators of health status: cribra orbitalia, porotic hyperostosis, trauma, infection, dental caries, abscesses, antemortem tooth loss, periodontal disease, and dental attrition. In addition, archeological and epidemiological data were used to help reconstruct the health of these populations. The goals of the analysis were 2-fold: 1) to assess the pre-contact health of North Alaskan Eskimos and Aleuts in order to provide a baseline comparison for the post-contact health of these groups, and 2) to determine if any differences in disease patterns exist between the Eskimos and Aleuts that might be related to differences in their physical environment, subsistence patterns, and cultural practices. The analysis revealed that both groups suffered from a variety of health problems prior to contact, including iron deficiency anemia, trauma, infection, and various forms of dental pathology. Statistical comparisons of the 2 groups revealed that Eskimos and Aleuts had different patterns of health and disease prior to contact. Most notably, the Aleuts had a significantly higher frequency of cranial trauma and infracranial infection than the Eskimos, while the latter had a significantly higher frequency of enamel hypoplasia. An examination of the physical and cultural environment of the 2 groups reveals several possible explanations for these differences, including warfare, subsistence pursuits, and housing practices. The documentation of these differences indicates that variability in pre-contact disease patterns can be identified between hunter-gatherer populations living in similar environments and exhibiting similar general lifestyles. Am J Phys Anthropol 107:51–70, 1998. © 1998 Wiley-Liss, Inc.     

Culture change and epidemiological patterns among the Hagahai,Papua New Guinea

The role of introduced epidemic disease in highland New Guinea is considered in light of recent debate concerning pre-contact adaptations. Seroepidemiological studies of the Hagahai, a small isolated group of hunterhorticulturalists in the fringe highlands of Papua New Guinea, document the recent introduction of mumps, hepatitis B, specific types of influenza, and rotavirus. Results are related to ethnographic findings, detailing past levels of intergroup contact and recent changes in settlement patterns, travel, feasting, health care, and other cultural factors. Data suggest that intergroup disease transmission is greatly increased decades before officially recorded time of contact and that mortality levels documented soon thereafter are not indicative of the pre-contact adaptation.     

Carbon and nitrogen stable isotopic signatures of human dietary change in the Georgia Bight.

Measurement of carbon and nitrogen stable isotope ratios (delta 13C and delta 15N) in samples of human bone collagen (n = 93) from a temporal series of four prehistoric (early preagricultural, late preagricultural, early agricultural, late agricultural) and two historic (early contact, late contact) periods from the Georgia Bight, a continental embayment on the southeastern U.S. Atlantic coast, reveals a general temporal trend for less negative delta 13C values and less positive delta 15N values. This trend reflects a concomitant decrease in emphasis on marine resources and increased reliance on C4-based resources, especially maize. This dietary reorientation is most apparent for the early agricultural sample (AD 1150-1300), coinciding with the Mississippian fluorescence in the eastern United States. There is, however, a shift toward the use of C3 (non-maize) foods during the last prehistoric period (AD 1300-1450), which is likely related to environmental stress and social disruption. A heavier use of maize and terrestrial resources in general after the establishment of mission centers on barrier islands is indicated. A reduced dietary breadth during the mission period may have contributed to the extinction of these populations in the eighteenth century.     

Gender differences exist in neuromuscular control patterns during the pre-contact and early stance phase of an unanticipated side-cut and cross-cut maneuver in 15–18 years old adolescent soccer players

Non-contact ACL injuries generally occur as the foot contacts the ground during cutting or landing maneuvers and the non-contact ACL injury rate is 2–8 times greater in females compared to males. To provide insight into the gender bias of this injury, this study set out to identify gender differences in the neuromuscular response of the quadriceps, hamstrings and gastrocnemii muscles in elite adolescent soccer players during the pre-contact and early stance phases of an unanticipated side-cut and cross-cut. For the early stance phase of the two maneuvers, females demonstrated greater rectus femoris activity compared to males. Throughout the pre-contact phase of the maneuvers, a rectus femoris activation difference was identified with females having an earlier and more rapid rise in muscle activity as initial ground contact approached. Females demonstrated greater lateral and medial gastrocnemii activity for the pre-contact and early stance phases of the side-cut and greater lateral gastrocnemii activity during early stance of the cross-cut. Timing of hamstring activity also differed between genders prior to foot contact. The differences suggest that the activation patterns observed in females might not be providing adequate joint protection and stability, thereby possibly having a contributing role towards increased non-contact ACL injuries in females.     

Dental anthropology and paleodemography of the precolumbian populations of hispaniola from the third millennium B.C. to the Spanish conquest

The demography and dental traits of the skeletal samples from the necropoles of Cueva Roja (IIrd millennium b.C.), El Soco (800 a.D) and Juan Dolio (1400 a.D.) have been analyzed. The preceramic sample from Cueva Roja consists of some 50 individuals, the one from El Soco consists of 158 individuals and the one from Juan Dolio of 108 individuals. The demographic analysis has revealed a slight improvement of life conditions from the pre-contact period to the beginning of the contact period. Dental metrical traits show a marked overlapping of the metrical data for the anterior teeth. A reduction can be noted for the posterior teeth, especially for the first molar, from the preceramic period to the later ceramic period. The analysis of nutritional stresses, through the study of dental enamel hypoplasias, reveals a high incidence of stress in the preceramic population. In the preceramic group, it peaks late in childhood (3.5—3.9 years of age) which could be caused by a delay in weaning. Instead the more recent groups (El Soco and Juan Dolio) show evidence of an earlier occurrence of hypoplasia. Both peak at 3.0–3.4 years of age. The frequencies of hypoplasias calculated by type of tooth are less in the Tainos groups than in the preceramic one. From of the data now available, we can suppose that an amelioration of life conditions occurred from the preceramic period to the later ceramic period. As regards the Tainos groups, a slight improvement in life conditions can be noted from the precontact period to the period immediately before the European colonization. The dental non-metric traits show a strong homogeneity within the Taino groups. However, the preceramic group shows more marked differences when compared to the others. This could be supposed to be due to a different demic background between the Tainos and the group from Cueva Roja.     

An assessment of health and disease in the prehistoric inhabitants of the Mariana Islands

Using a variety of skeletal and dental stress indicators, an assessment of the health and disease of the indigenous inhabitants of the Mariana Islands, the Chamorro, is made. The major hypothesis to be tested is that the Chamorro were relatively healthy and that deviations from the expected, as well as inter-island variation, may reflect environmental, ecological, and cultural differences. The major skeletal series surveyed include sites on Guam (N = 247 individuals), Rota (N = 14), Tinian (N = 20), and Saipan (N = 102). The majority of the specimens are from the transitional pre-Latte (AD 1–1000) and Latte (AD 1000–1521) periods. These data derive primarily from unpublished osteological reports. The indicators of health and disease surveyed include mortality and paleodemographic data, stature, dental paleopathology, cribra orbitalia, limb bone fractures, degenerative osteoarthritis, and infectious disease (including treponemal infection). Where appropriate, tests of significance are calculated to determine the presence of any patterning in the differences observed within and between the skeletal series. Information recorded in prehistoric Hawaiians provides a standard for external comparisons. Several of the larger skeletal series surveyed have paleodemographic features that are consistent with long-term cemetery populations. Females and subadults are typically underrepresented. Most subadult deaths occur in the 2–5 year age interval. Life expectancy at birth ranges from 26.4 to 33.7 years. A healthy fertility rate is indicated for these series. The prehistoric inhabitants of the Mariana Islands were relatively tall, exceeding living Chamorros measured in the early part of the present century. The greater prevalence of developmental defects in the enamel suggests that the Chamorro were exposed to more stress than prehistoric Hawaiians. The low frequency of cribra orbitalia further indicates iron deficiency anemia was not a problem. There are generally low frequencies of dental pathology in the remains from the Mariana Islands. Betel-nut staining is relatively common in all series which may help to explain the relatively low prevalence of dental pathology. Healed limb bone fractures are rare in these skeletal series; the frequency and patterns of fractures suggest accidental injury as the main cause. Greater physical demands involving the lower back region are indicated by a high frequency of spondylolysis, or stress fracture in the lumbar vertebrae in the Chamorro. Likewise, advanced degenerative bone changes, while of low occurrence, are significantly greater in the Chamorro than Hawaiians. The prevalence of skeletal and dental indicators of stress was generally higher in the smaller islands of the Marianas chain (e.g., Rota), islands with fewer resources to buffer environmental catastrophe. Bony changes suggestive of treponemal (probably yaws) disease are common in most of these Marianas Islands skeletal series. Am J Phys Anthropol 104:315–342, 1997. © 1997 Wiley-Liss, Inc.     

Whole genome sequencing to investigate the emergence of clonal complex 23 Neisseria meningitidis serogroup Y disease in the United States

In the United States, serogroup Y, ST-23 clonal complex Neisseria meningitidis was responsible for an increase in meningococcal disease incidence during the 1990s. This increase was accompanied by antigenic shift of three outer membrane proteins, with a decrease in the population that predominated in the early 1990s as a different population emerged later in that decade. To understand factors that may have been responsible for the emergence of serogroup Y disease, we used whole genome pyrosequencing to investigate genetic differences between isolates from early and late N. meningitidis populations, obtained from meningococcal disease cases in Maryland in the 1990s. The genomes of isolates from the early and late populations were highly similar, with 1231 of 1776 shared genes exhibiting 100% amino acid identity and an average π(N) = 0.0033 and average π(S) = 0.0216. However, differences were found in predicted proteins that affect pilin structure and antigen profile and in predicted proteins involved in iron acquisition and uptake. The observed changes are consistent with acquisition of new alleles through horizontal gene transfer. Changes in antigen profile due to the genetic differences found in this study likely allowed the late population to emerge due to escape from population immunity. These findings may predict which antigenic factors are important in the cyclic epidemiology of meningococcal disease.     

Population history of native groups in pre- and postcontact Spanish Florida: aggregation, gene flow, and genetic drift on the Southeastern U.S. Atlantic coast

Evolutionary trends and population history and structure are discussed for a series of late prehistoric and historic-period skeletal samples from the Georgia coast and interior (the Guale). Phenotypic dental measurement data were collected for nine samples from the late prehistoric (AD 1200-1400) and historic (AD 1608-1702) periods and subjected to population genetic and statistical analyses. The primary trends were for an increase in tooth size through time, and for an initial increase in dental variability in the early historic period, followed by a subsequent decline in dental variability in the late historic period. Given the increasing stress levels, evidenced by previous bioarchaeological analyses (Larsen [2001] Bioarchaeology of Spanish Florida, Gainesville: University Press of Florida), an environmental explanation for the increase in tooth size is unlikely. It is proposed that the early historic period witnessed aggregation and gene flow with extraregional populations, possibly African slaves or nonlocal Native American population groups. The late historic period may have experienced significant loss of phenotypic variability due to genetic drift. In both time periods, the evolutionary mechanism increased average tooth size, with independent variance effects.Because microevolutionary trends obscure patterns of gene flow and population ancestry, the data were detrended following Konigsberg ([1990a] Hum. Biol. 62:49-70), and submitted to standard population genetic analyses (Relethford et al. [1997] Hum. Biol. 69:443-465). Analysis of the precontact samples in isolation (Irene Mound, Irene Mortuary, and an aggregate coastal sample) indicated little genetic microdifferentiation (F(ST) = 0.008), limited extralocal gene flow, and a small distinction between interior and coastal samples. The inclusion of the historic data dramatically increased variability levels (F(ST) = 0.019). The analysis of extralocal gene flow indicates that the late mission period experienced significantly less external gene flow, which is consistent with historic models that suggest the social organization of the Guale during this time period may have been significantly altered. Genetic distances also indicate a primary division between inland and coastal precontact samples and a maintenance of biological populations along the coast. In other words, the coastal, early historic, and late historic period samples are phenotypically homogeneous, supporting the notion that the mission populations were drawn from the local population base. The late mission period sample was also, however, more closely related to the interior samples. This may suggest that the late mission period population was an aggregate sample composed of both remnant interior and coastal population groups.     

Effects of acute and chronic oval exposure of lead on blood pressure and bone mineral density in rats

The immediate and late deleterious effects of early lead (Pb) exposure on human health are major challenges to the health professionals. Therefore, a major underlying contribution of Pb accumulated earlier in life to chronic disorders such as hypertension and osteopenia, commonly found in the elderly, cannot be definitively excluded. Using Sprague-Dawley rats, we examined the effects of drinking 1% Pb acetate on very young rats for 40 days on Pb kinetics, body weight (BW), systolic blood pressure (SBP) and bone mineral density (BMD) over a year-long period. We also examined the effects of early and later chelation using disodium calcium ethylenediaminetetraacetate (Na2CaEDTA). The early ingestion and accumulation of Pb was associated with an increased SBP acutely that returned to control levels with continuing challenge and later rose above control months later after the Pb challenge had been halted. Early accumulation of Pb over a short period was also associated with decreased BMD at the end of one year. Chelation after the initial Pb challenge at various times favorably influenced the SBP but could not prevent the lowering of BMD.     

Long bone lengths and gestational age distributions of post-contact period Arikara Indian perinatal infant skeletons

Prenatal growth is adversely affected by poor socioeconomic conditions where disease and chronic undernutrition prevail. Premature and small-for-gestational-age births occur at higher frequency. Post-contact Arikara Indian populations of South Dakota experienced a rapidly changing and disruptive environment that included deterioration of the subsistence base and increased morbidity. This research tests resulting fetal growth effects through comparative analysis of two perinatal infant samples of the early (A.D. 1600-1733) and the late (A.D. 1760-1835) post-contact period. Perinatal infants recovered from late cemeteries include a higher percentage of smaller skeletons, as determined using long bone diaphyseal lengths, than is documented for the earlier time period. This contrast shows that it is possible to detect fetal growth differences in samples of archaeological context.     

Growth-related shape changes in the fetal craniofacial complex of humans (Homo sapiens) and pigtailed macaques (Macaca nemestrina): a 3D-CT comparative analysis

This study investigates whether macaques and humans possess a common pattern of relative growth during the fetal period. The fetal samples consist of 16 male pigtailed macaques (mean age, 20.5 gestational weeks) and 17 humans (9 males and 8 females; mean age, 29.5 gestational weeks). For each individual, three-dimensional coordinates of 18 landmarks on the skull were collected from three-dimensional computed tomographic (CT) reconstructed images and two-dimensional CT axial slices. Early and late groups were created from the human (early mean age, 24 weeks, N = 8; late mean age, 34 weeks, N = 9) and macaque samples (early mean age, 17.7 weeks, N = 7; late mean age, 23 weeks, N = 9). Inter- and intraspecific comparisons were made between the early and late groups. To determine if macaques and humans share a common fetal pattern of relative growth, human change in shape estimated from a comparison of early and late groups was compared to the pattern estimated between early and late macaque groups. Euclidean distance matrix analysis was used in all comparisons. Intraspecific comparisons indicate that the growing fetal skull displays the greatest amount of change along mediolateral dimensions. Changes during human growth are primarily localized to the basicranium and palate, while macaques experience localized change in the midface. Interspecific comparisons indicate that the two primate species do not share a common pattern of relative growth, and the macaque pattern is characterized by increased midfacial growth relative to humans. Our results suggest that morphological differences in the craniofacial skeleton of these species are in part established by differences in fetal growth patterns.     

ANNUAL REPRODUCTIVE CYCLE OF THE FEMALE HAWAIIAN MONK SEAL (MONACHUS SCHAUINSLANDI)

Abstract: The annual reproductive cycle is described for the adult female Hawaiian monk seal ( Monachus schauinslandi ) from data collected at Laysan Island (1982–1991) and Lisianski Island (1982–1983) in the Northwestern Hawaiian Islands. Pupping, lactation, weaning, and molting were directly observed, while mating was rarely observed and was, therefore, inferred from the occurrence of mounting injuries and from adult male and female association patterns. Pooled birth rates during the study period were 0.544 for all adult-sized females and 0.675 for females parous in earlier years. For parturient females, pupping peaked in late March and early April, weaning in May, mounting injuries in May and June, and molting in July. For non-parturient females, the median mounting injury and molting dates occurred 17 and 28 days earlier, respectively. Pupping date set the timing of subsequent events in the annual cycle, but the timing of those events was adjusted by loss of the pup or poor physical condition of the female. Individual pupping patterns varied widely. The mean interval for births in consecutive years was 381 days; females that pupped in consecutive years gave birth later each season. Conversely, females who skipped a year or more gave birth earlier their next pupping season.     

Stable nitrogen and carbon isotope ratios in bone collagen as indices of prehistoric dietary dependence on marine and terrestrial resources in southern California

The ratios of 15N to 14N and 13C to 12C tend to be higher in marine than in terrestrial organisms. The concentrations of these isotopes in human bone collagen consequently can be used to make inferences about the contribution of marine and terrestrial resources to prehistoric diets. The utility of studying 15N/14N and 13C/12C ratios in conjunction with each other is illustrated by our analysis of 40 human burials from archaeological sites in the Santa Barbara Channel area of southern California. The mean delta 13C and delta 15N values (in per mil) of collagen from these skeletons decrease progressively from the Channel Islands (delta 13C = -14.0, delta 15N = +16.3) to the mainland coast (delta 13C = -14.5, delta 15N = +14.9) to the interior (delta 13C = -17.2, delta 15N = +10.9). These data suggest that Indians living on the Channel Islands during the late prehistoric period were heavily dependent on marine resources. The inhabitants of the mainland interior, in contrast, had a diet composed largely of terrestrial foods. From their isotope ratios, it appears that the Indians who lived on the mainland coast consumed a mixed diet containing substantial quantities of both marine and terrestrial resources. Differences in 15N/14N and 13C/12C ratios of individuals from mainland sites dating from the early and late prehistoric periods show that the marine component of the diet increased substantially through time. These isotopic data are consistent with pathological, faunal, and artifactual evidence of increased marine resource exploitation during the late prehistoric period.     

Latent activity rhythm disturbance sub-groups and longitudinal change in depression symptoms among older men

Activity rhythm disturbances and depression often co-occur among older adults. However, little is known about how activity rhythm disturbances themselves co-occur, or how disturbances to multiple aspects of the activity rhythm relate to depression over time. In this study, we performed a Latent Class Analysis to derive sub-groups of older men [total n?=?2933, mean age?=?76.28, standard deviation (SD)?=?5.48] who shared similar patterns of activity rhythm disturbances (defined as extreme values of modeled activity rhythm parameters). We found eight sub-groups with distinct combinations of activity rhythm disturbances: one had all normative activity rhythm parameters (32.09%), one had only lower activity (10.06%), three had earlier activity (totaling 26.96%) and three had later activity (totaling 30.89%). Groups with similar timing were distinguished depending on whether the relative length of the active period was shorter and/or if the activity rhythm had lesser amplitude/robustness. We next examined whether the derived activity rhythm sub-groups were associated with different rates of change in depression symptom levels over an average of 5.5 (0.52 SD) follow-up years. The sub-group with lower activity only had faster increases in depressive symptoms over time (compared with the group with normative rhythm parameters), but this association was accounted for by adjustments for concurrently assessed health status covariates. Independent of these covariates, we found that four activity rhythm disturbance sub-groups experienced faster depressive symptom increases (compared with the normative sub-group): These included all three sub-groups that had later activity timing and one sub-group that had earlier activity timing plus a shorter active period and a dampened rhythm. Low activity rhythm height/robustness with normal timing therefore may mark depression risk that is attributable to co-occurring disease processes; in contrast, having late or combined early/compressed/dampened activity rhythms may independently contribute to depression symptom development. Our findings suggest that activity rhythm-related depression risk is heterogeneous, and may be detected when multiple aspects of rhythm timing are delayed or when early timing is accompanied by compressed/dampened activity rhythms. Future studies should consider how distinct combinations of altered activity rhythm timing and height/robustness develop and conjointly determine health risks. Further research is also needed to determine whether/how activity rhythms can be modified to improve depression outcomes.     

Irrigation and infection: the immunoepidemiology of schistosomiasis in ancient Nubia

Schistosomiasis has been deemed "the most important water-based disease from a global public-health perspective" in modern populations. To better understand the burden of schistosomiasis in ancient populations, we conducted immunologic examinations of desiccated tissue samples from two ancient Nubian populations, Wadi Halfa (N = 46) and Kulubnarti (N = 191). Saqia irrigated agriculture increases the available habitat for the aquatic vector snails and the risk of exposure. On the basis of evidence regarding the impact of saqia irrigation on schistosomiasis prevalence and transmission in modern populations, we predicted that the prevalence of Schistosoma mansoni infection would be higher in Wadi Halfa (saqia irrigation) than Kulubnarti (annual flooding). We also predicted that peak infection prevalence would occur at an earlier age within the Wadi Halfa population than the Kulubnarti population and that in both populations the prevalence of schistosomiasis would be higher in males than females due to differential water contact. The prevalence of S. mansoni was greater in the Wadi Halfa population (26.1%) than at Kulubnarti (9.4%) (P = 0.002). However, peak prevalence of infection did not occur in a younger age category within the Wadi Halfa population; prevalence of infection peaked at 66.7% in the mature adult age group (46+ years) in the Wadi Halfa population and at 16% in the later child age group (6-10 years) in the Kulubnarti population. There were no statistically significant differences in prevalence between males and females of either population. The impact of human alteration of the environment on the transmission of schistosomiasis is clearly shown in these populations.     

Patterns of long-bone fracture in two nubian cementeries

The analysis of traumatic fractures can provide valuable information concerning the affects of sociopolitical factors upon the health of prehistoric populations. However, such information can only be acquired by implementing a quantitative demographic approach. The present research applies such a method to longbone fractures in two medieval Christian populations excavated from ancient Nubia. Long-bones of two hundred and eighteen individuals from an early (550 to 750 A.D.) Christian cemetery and 188 individuals from a late (750 to 1450 A.D.) Christian cemetery were examined for evidence of traumatic fracture. Analysis included a determination of fracture rates, age and sex related fracture patterns, and rate of fracture per years at risk. The results of this study indicate that the majority of fractures in both cemeteries were likely caused by accidental falls. Fractures resulting from direct (possibly interpersonal) violence were found in both samples, though at a higher frequency in the early Christian population (27% versus 16%). Middle-aged adults (particularly males) of the early cemetery exhibited a higher than expected risk to fractures indicating an activity related cause of injury. In contrast, the late Christian population showed a marked increase in fractures among both children and the elderly. This distribution may reflect changes in health and residential architecture which occurred during the late Christian period.     

Forecasting seasonal population growth of Aphis glycines (Hemiptera: Aphididae) in soybean in Illinois

From 2001 to 2004, 252 fifty-plant samples were collected from commercial soybean, Glycine max L., fields in three townships (93-km2 area) in Illinois. Townships were sampled every 3 wk from late June or early July when aphids (Aphis glycines Matsumura) first invaded the townships to early August. We used linear regression of 18 mean township field densities to calibrate several simple models to predict the change in aphid population density in a township from one sampling date to the next. The best exponential model for the complete data set has an r2 = 0.54, Y2 = Ylexp (0.09659 x DAY), where Y1 and Y2 are the first and second samples of aphids separated by a 3-wk period (the number of days, DAY). Our intrinsic rate of increase for the population is much lower than rates calculated in other studies. The best single-variable linear model has an r2 = 0.88, Y2 = Y1 + 0.1084 x Y1 x DAY. The latter model indicates the value of including monitoring data in the prediction. The best two-variable model has an R2 = 0.98, Y2 = Y1 + 0.08136 x Y1 x DAY + 0.000080 x N1(2) x DAY, where N1(2) x DAY is the interaction term for initial, squared, sample density of the season multiplied by the number of days between samples. The latter two models indicate that the change in the population density is greater for more dense populations. Degree-days were generally inferior to days as the time component in the simple models.     

Population history of Berthelot's pipit: colonization, gene flow and morphological divergence in Macaronesia

The fauna of oceanic islands provide exceptional models with which to examine patterns of dispersal, isolation and diversification, from incipient speciation to species level radiations. Here, we investigate recent differentiation and microevolutionary change in Berthelot's pipit (Anthus berthelotii), an endemic bird species inhabiting three Atlantic archipelagos. Mitochondrial DNA sequence data and microsatellite markers were used to deduce probable colonization pathway, genetic differentiation, and gene flow among the 12 island populations. Phenotypic differentiation was investigated based on eight biologically important morphological traits. We found little mitochondrial DNA variability, with only one and four haplotypes for the control region and cytochrome b, respectively. However, microsatellite data indicated moderate population differentiation (FST=0.069) between the three archipelagos that were identified as genetically distinct units with limited gene flow. Both results, combined with the estimated time of divergence (2.5 millions years ago) from the Anthus campestris (the sister species), suggest that this species has only recently dispersed throughout these islands. The genetic relationships, patterns of allelic richness and exclusive alleles among populations suggest the species originally colonized the Canary Islands and only later spread from there to the Madeiran archipelago and Selvagen Islands. Differentiation has also occurred within archipelagos, although to a lesser degree. Gene flow was observed more among the eastern and central islands of the Canaries than between these and the western islands or the Madeiran Islands. Morphological differences were also more important between than within archipelagos. Concordance between morphological and genetic differentiation provided ambiguous results suggesting that genetic drift alone was not sufficient to explain phenotypic differentiation. The observed genetic and morphological differences may therefore be the result of differing patterns of selection pressures between populations, with Berthelot's pipit undergoing a process of incipient differentiation.     

Differential phenotypic variability among the Apalachee mission populations of La Florida: a diachronic perspective

Phenotypic variability is evaluated in a series of skeletal samples from the Apalachee region of Florida. Based on ethnohistoric evidence, several predictive models for changes in variability are generated. If variability decreases through time, this likely represents the effect of genetic drift in populations experiencing epidemic disease and population loss. If variability increases through time, this suggests that population aggregation or genetic admixture were primary factors shaping the Apalachee population during the mission period. Dental dimensions were collected from a series of precontact (pre-1500), early mission (AD 1633-1650) (San Pedro y San Pablo de Patale), and late mission (post-1657) (San Luis) samples from the Apalachee region and were subjected to univariate and multivariate variability analyses. The results indicate that the late mission San Luis sample was significantly more variable than the Patale or precontact samples; however, the Patale sample exhibited no significant variability change in comparison to the precontact population. This suggests that the missions initially effected limited change in genetic variability in the mission populations. However, San Luis was affected by either admixture or population aggregation to such a degree that the observed variation had increased beyond earlier levels. Given the limited historic evidence for population aggregation at this mission, and the comparatively large resident Spanish population, the increased variability may be indicative of admixture at this mission, and potentially at this mission only. Based on a limited data set, however, it appears that the mission period cannot be typified by a single evolutionary or historic process.     

Genetic Divergence of an Avian Endemic on the Californian Channel Islands

The Californian Channel Islands are near–shore islands with high levels of endemism, but extensive habitat loss has contributed to the decline or extinction of several endemic taxa. A key parameter for understanding patterns of endemism and demography in island populations is the magnitude of inter–island dispersal. This paper estimates the extent of migration and genetic differentiation in three extant and two extinct populations of Channel Island song sparrows (Melospiza melodia graminea). Inter–island differentiation was substantial (G''''_ST: 0.14–0.37), with San Miguel Island having the highest genetic divergence and lowest migration rates. Santa Rosa and Santa Cruz Island populations were less diverged with higher migration rates. Genetic signals of past population declines were detected in all of the extant populations. The Channel Island populations were significantly diverged from mainland populations of M. m. heermanni (G''''_ST: 0.30–0.64). Ten mtDNA haplotypes were recovered across the extant and extinct Channel Island population samples. Two of the ten haplotypes were shared between the Northern and Southern Channel Islands, with one of these haplotypes being detected on the Californian mainland. Our results suggest that there is little contemporary migration between islands, consistent with early explanations of avian biogeography in the Channel Islands, and that song sparrow populations on the northern Channel Islands are demographically independent.