Wild Meat Use and Traditional Hunting Practices in a Rural Mayan Community of the Yucatan Peninsula,Mexico

Overexploitation of Neotropical ecosystems for wild meat constitutes a threat to biodiversity and might seriously affect local people who depend on wild animals as a primary food resource. To assess this problem at the local level, social use of wild animals was evaluated in a Mayan community of the Yucatan Peninsula. Over 8 months, peasant-hunters carried out a total of 175 hunting trips, gathering 253 animals of 12 species (mammals, birds and reptiles). Most preys (95%) were taken in 4 months (January–April) during the dry season and the main target species were white-tailed deer and iguana (jointly representing 59% of preys). During an 11-week period, total per capita wild meat consumption (182 kg; n = 14 families) was three times greater in nuclear than in extended families. The observed wild fauna use is a reflection of traditional knowledge and represents an important subsistence strategy for the local people.     

Heritability of age at menarche in girls from the Fels Longitudinal Study

Menarche is the hallmark maturational event of female childhood. Many studies indicated a significant genetic contribution to the timing of the onset of menstruation, but most of these studies were limited by the use of retrospective data and by the use of data from only certain types of relatives (i.e., mothers and daughters, sisters, or twin sisters). The primary goal of this study was to use a modern maximum likelihood quantitative genetic method to estimate the heritability (h(2)) of age at menarche, using familial data collected over the course of the 74-year-old Fels Longitudinal Study. The secondary goal was to review earlier studies of the heritability of age at menarche. The study of the heritability of age at menarche presented here is unique for two reasons. First, because of the Fels Longitudinal Study's serial design, age-at-menarche data were collected prospectively from most participants. Second, because the Fels Longitudinal Study is a family study that has been conducted for decades, age-at-menarche data are available from many types of female relatives spanning multiple households and generations. The best-fitting and most parsimonious quantitative genetic model included provision for a secular decrease in age at menarche, and estimated the h(2) of age at menarche to be 0.49+/- 0.13 (95% confidence interval of h(2),=0.24-0.73). The results of this study are in general agreement with the findings of most previous studies of genetic influences on age at menarche, and suggest that it is reasonable to consider it well-established that approximately half the phenotypic variation among girls from developed nations in the timing of menarche is due to genetic factors.     

Changes in age at menarche in Spain (1909–1965)

The data used in this work have been collected from clinical histories of women who have been examined at the Ginecology and Obstetritian Service of the Santa cruz y San Pablo Hospital of Barcelona. The sample consisted of 12,803 Spanish women, born between 1909 and 1965, by regions of birth. The method used is retrospective. The maximum menarcheal age in Spain (13.91±0.049 years) is found among those women born between 1925 and 1929 and the minimum menarcheal age (12.92±0.036 years) among women born between 1955 and 1959; so in an interval of 30 years, a reduction of almost a year (11.88 months) has taken place in age at first menstruation. This means a reduction of almost four months per decade. These differences are significant (p=.0000). The higher menarcheal age appears in the Northern Zone, due to the influence of Galicia in the sample (Galicia being a depressed zone with a great emigration rate). The earliest menarcheal age appears in the Mediterranean Zone due to the great percentage of catalan women (Catalonia being a region with a higher socioeconomical level). It is also to be observed that although the menarcheal age has decreased in all the zones, it has done so more dramatically in those zones which had higher values at the beginning. Although the secular trend of reduction in the age at menarche varies greatly from region to region, it may be considered that, in general, the socieconomic conditions have been the decisive factor in the change in physical maturation of Spanish women.     

Genetic confounding of the relationship between father absence and age at menarche

Research in evolutionary psychology, and life history theory in particular, has yielded important insights into the developmental processes that underpin variation in growth, psychological functioning, and behavioral outcomes across individuals. Yet, there are methodological concerns that limit the ability to draw causal inferences about human development and psychological functioning within a life history framework. The current study used a simulation-based modeling approach to estimate the degree of genetic confounding in tests of a well-researched life history hypothesis: that father absence (X) is associated with earlier age at menarche (Y). The results demonstrate that the genetic correlation between X and Y can confound the phenotypic association between the two variables, even if the genetic correlation is small—suggesting that failure to control for the genetic correlation between X and Y could produce a spurious phenotypic correlation. We discuss the implications of these results for research on human life history, and highlight the utility of incorporating genetically sensitive tests into future life history research.     

Biological traits and living conditions of Maya Indian and non Maya girls from Merida,Mexico

A total of 522 girls and their families from low and middle social strate were examined in the northern part of Merida (Yucatan) during 1988 and 1989. Marital radius in the parental generation was relatively long (146 km), and it was six times longer for non-Maya and mixed couples than Maya. Living and housing conditions were similar for both Maya and non-Maya (mixed couples typically had an intermediate condition), except for sewage system (sanitation). The Maya income was 64% lower. Maya men and women were short. The girls from Merida were short, hyper-brachycephalic (short headed), and europrosopic (broad face). Among them, Maya girls were even shorter, more round-headed, and more broad-faced than non-Maya girls. Menarche occurred on the average at an age of 12.6 years in mothers and 12.1 years in daughters. As the generation time was about 25 years, there was a slow acceleration of maturation (0.2 years per decade). Presumably, also stature has increased in recent years.     

Breast cancer susceptibility loci in association with age at menarche,age at natural menopause and the reproductive lifespan

Background: Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with breast cancer risk. Some of these loci have unknown functional significance and may mediate the effects of hormonal exposures on breast cancer risk. We examined relationships between breast cancer susceptibility variants and menstrual/reproductive factors using data from two population-based studies. Methods: The first analysis was based on a sample of 1328 women age 20–74 who participated as controls in a case–control study of breast cancer conducted in three U.S. states. We evaluated the associations between age at menarche, age at natural menopause and the reproductive lifespan with 13 previously identified breast cancer variants. Associations were also examined with a genetic score created as the sum of at-risk alleles across the 13 variants. For validation, significant results were evaluated in a second dataset comprised 1353 women age 43–86 recruited as part of a cohort study in Wisconsin. Results: Neither the genetic score nor any of the 13 variants considered individually were associated with age at menarche or reproductive lifespan. Two SNPs were associated with age at natural menopause; every increase in the minor allele (A) of rs17468277 (CASP8) was associated with a 1.12 year decrease in menopause age (p = 0.02). The minor allele (G) of rs10941679 (5p12) was associated with a 1.01 year increase in age at natural menopause (p = 0.01). The results were not replicated in the validation cohort (B = −0.61, p = 0.14 and B = −0.01, p = .0.98, respectively). Conclusions: The evaluated variants and reproductive experiences may work through separate pathways to influence breast cancer risk.     

A1298C polymorphism of the MTHFR gene and neural tube defects in the state of Yucatan, Mexico

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) of the folate metabolism pathway is a candidate gene for neural tube defects (NTDs). Frequency of the second common polymorphism, A1298C, in the MTHFR gene is not well known in Mexico. Conflicting results exist regarding the association of A1298C-MTHFR with NTDs. One explanation for this controversy might be that alleles are differently distributed among various populations. The aim of the study was to determine the frequency of the A1298C-MTHFR polymorphism and its association with NTDs in a population of Yucatan, Mexico. METHODS: Genotyping was performed by use of polymerase chain reaction with restriction fragment length polymorphisms using MbOII endonuclease (PCR-RFLPs MbOII). Allele and genotype frequencies were compared between cases with NTDs, their mothers and fathers with matched controls based on an association analysis using EpiInfo software. RESULTS: A1298C genotypes were distributed according to Hardy-Weinberg expectations for all studied groups. Frequencies of allele C and heterozygous AC genotype were significantly higher in males (p = .006 and p = .011, respectively) in control group. Significant differences were not observed between cases and controls, except in mothers of NTD cases compared with mothers of healthy offspring for both allele C and heterozygous AC genotype (p = .009 and p = .01, respectively). CONCLUSIONS: The polymorphism A1298C-MTHFR is not associated with NTDs, except for mothers, suggesting only a maternal association with having NTD-affected offspring in the Yucatan population. The frequency of allele C in the control population was 10%, which is significantly lower than in other reported control populations worldwide (p < .01).     

A Survey of Dog Populations in Urban and Rural Areas of Yucatan,Mexico

ABSTRACT

A survey in a major Mexican city (Merida) and three rural communities was conducted to generate information regarding the size and structure of the owned-dog populations and people's opinions about the dogs and how they took care of them. Household characteristics and dog population size, health and reproductive issues were compared between the two kinds of communities: urban and rural. A telephone survey was conducted in Merida city whereas personal interviews were used in the rural communities. Local veterinarians were also interviewed to evaluate their influence on the dog populations in Merida city. The ratio of people to dogs was 3.4:1 in the city, and 1.7:1 to 4.6:1 in the different rural communities. In general it was more common to find a dog-owning household in the city of Merida (72.8%) than in the rural areas (63.6%, 65.5% and 71.1%), and in the city more households had adequate fences to restrain dogs. Larger families were more likely to own a dog than small families. Households of medium socio-economic status had a significantly higher probability of owning a dog than households of low or high socio-economic status. Of the dogs in the city, 90.1% were vaccinated against rabies compared with 62.3% of the dogs in the rural communities. Most animals were intact; the frequency of neutering/spaying was 3.1% in Merida and 1.8% in the rural communities. Few private veterinary practitioners were involved in the control of dog overpopulation. It is concluded that dogs are popular pets both in urban and rural Yucatan. People's opinions about dogs and the level of supervision varied with socio-economic status, and people in the city provided better food, shelter and preventive medicine. The veterinary practitioners did little to promote the control of dog breeding or to reduce the relinquishing of unwanted dogs in the city. Better client education and the promotion of sterilization of pets at low cost would improve the situation.     

Antifungal properties of selected plants from the Yucatan peninsula,Mexico

A total of 20 plants belonging to different genera (Acalypha, Ageratum, Ambrosia, Bidens, Blechum, Caesalpinia, Calea, Carlowrightia, Croton, Eugenia (2), Furcraea, Stenandrium, Tephrosia, Trichilia (2), Randia (3), and Vitex) were selected from native flora of the Yucatan peninsula. All plants selected were collected and separated in to leaves, stems and roots. These were then extracted with ethanol and their crude extracts (54) were evaluated against Alternaria tagetica, Colletotrichum gloeosporioides, Fusarium oxysporum and Rhizopus sp. using the filter paper disc diffusion assay. Results lead to the selection of 33 crude extracts active against at least one of the target strains, which were assessed to determine their ability to inhibit the mycelial growth of the pathogenic fungi in a second antifungal assay. The results of this assay indicated that extracts from the roots of Croton chichenensis were the most promising, with a wide activity spectrum against all pathogens tested in both assays with inhibition percentages of greater than 60%. Furthermore, extracts from leaves of Ambrosia hispida, Trichilia minutiflora, and roots of Acalypha gaumeri were able to cause growth inhibition against two or three pathogen strains (≥50%). Studies of these active extracts should be continued at different levels. In general, results revealed a good bioactive potential of the flora from the Yucatan peninsula to produce metabolites with potential applications as botanical pesticides in the near future.     

Fatness and fat patterning in relation to age changes and menarche

The present study assesses changes with age in fatness and fat patterning in a cross-sectional sample of Spanish schoolgirls from 6 to 16 years of age living in an urban area (Madrid). Arm muscle area and arm fat area were derived from middle-upper arm anthropometry. Body mass index (weight/height²) and the sum of the skinfold thicknesses at three sites (triceps, subscapular and suprailiac) were computed as indices of adiposity; and two indices of subcutaneous fat distribution were also defined: the natural logarithms of subscapular/triceps and suprailiac/triceps skinfold thickness ratios. Changes with age in these variables are described, including some pattern changes found in amount of fatness as well as in fat distribution at pubescence. At this time, there is a plateau in fat deposition, and even a fat loss the average (at triceps site). Prior to pubescence, subcutaneous fat distribution changes from «pheripheral» to a more generalized pattern, but no well-defined pattern of change is found after the onset of menarche. Furthermore, the effect of the onset of puberty on all these variables is analyzed.     

HDC gene polymorphisms are associated with age at natural menopause in Caucasian women

Histidine decarboxylase gene (HDC) encodes histidine decarboxylase which is the crucial enzyme for the biosynthesis of histidine. Studies have shown that histamine is likely to be involved in the regulation of reproduction system. To find the possible correlation between HDC gene and AANM (age at natural menopause), we selected 265 postmenopausal women from 131 nuclear families and performed a transmission disequilibrium test. Significant within-family associations with AANM for SNP rs854163 and SNP rs854158 of HDC gene were observed (P values=0.0018 and 0.0197, respectively). After 1000 permutations, SNP rs854163 still remained significant within-family association with AANM. Consistently, we also detected a significant within-family association between haplotype block 2 (defined by SNP rs854163 and rs860526) and AANM in the haplotype analyses (P value=0.0397). Our results suggest that the HDC gene polymorphisms are significantly associated with AANM in Caucasian women.     

Early stress predicts age at menarche and first birth,adult attachment,and expected lifespan

Life history theory suggests that in risky and uncertain environments the optimal reproductive strategy is to reproduce early in order to maximize the probability of leaving any descendants at all. The fact that early menarche facilitates early reproduction provides an adaptationist rationale for our first two hypotheses: that women who experience more risky and uncertain environments early in life would have (1) earlier menarche and (2) earlier first births than women who experience less stress at an early age. Attachment theory and research provide the rationale for our second two hypotheses: that the subjective early experience of risky and uncertain environments (insecurity) is (3) part of an evolved mechanism for entraining alternative reproductive strategies contingent on environmental risk and uncertainty and (4) reflected in expected lifespan. Evidence from our pilot study of 100 women attending antenatal clinics at a large metropolitan hospital is consistent with all four hypotheses: Women reporting more troubled family relations early in life had earlier menarche, earlier first birth, were more likely to identify with insecure adult attachment styles, and expected shorter lifespans. Multivariate analyses show that early stress directly affected age at menarche and first birth, affected adult attachment in interaction with expected lifespan, but had no effect on expected lifespan, where its original effect was taken over by interactions between age at menarche and adult attachment as well as age at first birth and adult attachment. We discuss our results in terms of the need to combine evolutionary and developmental perspectives and the relation between early stress in general and father absence in particular. This work was supported by The University of Melbourne Department of Obstetrics and Gynaecology. James S. Chisholm is Professor in the School of Anatomy and Human Biology at the University of Western Australia. He is an anthropologist whose interests lie in the fields of human behavioral biology, evolutionary ecology, life history theory, and parental investment theory, where he focuses on infant social-emotional development, the development of reproductive strategies, and the integration of evolutionary, developmental, and cultural psychology and public health. Julie A. Quinlivan is Associate Professor in Obstetrics and Gynaecology at the University of Melbourne and Head of the Maternity Care Program at the Royal Women’s Hospital, Melbourne. Her interests are teenage pregnancy, domestic violence, child abuse prevention, and high-risk pregnancy. Rodney W. Petersen is Senior Lecturer in Obstetrics and Gynaecology at the University of Melbourne and Senior Consultant in Obstetrics and Gynaecology at the Royal Women’s Hospital and Sunshine Hospital in Melbourne. His interests are in psychosocial aspects of women’s health and cancer. David A. Coall is a Ph.D. student in the School of Anatomy and Human Biology at the University of Western Australia. His main interest lies in the application of evolutionary theory within an epidemiological framework. He is currently working on the synthesis of life history theory, parental investment theory, and parent-offspring conflict theory in exploring factors that influence variation in human birth weight and placental weight.     

Quantitative Assessment for Selecting the Route for a Gas Pipeline in Yucatan,Mexico

A quantitative comparative assessment was used to decide the best route for constructing a gas pipeline in the state of Yucatan, Mexico. Two alternative routes were assessed. The focus of the analysis was to develop an integrated assessment that would help minimize land degradation by economic development activities, taking into account the impact on physical and biological resources, and on human population. The ecological impact, the potential risk of an accident, and the cost for both alternatives were considered. The significance of the impact depends on the relative importance and quantity of components to be affected by the pipeline along both routes. In this work, a method for the ecological assessment of the alternative routes was used and an index was used for risk assessment considering the possibilities of pipeline damage by local people, the amount of agricultural activities, inflexion points, and topography along the route. The analysis indicated that the ecological impact, risk of accident, and cost are lower by constructing the pipeline along the recommended route. Population density along the alternative route was higher than on the recommended one. The results of the analysis were submitted to the Mexican Environmental Ministry and the pipeline project was approved in 1997.     

Migration timing and distance from shore of southbound eastern Pacific gray whales (Eschrichtius robustus) off Ensenada,Baja California,Mexico

Eastern Pacific gray whales were monitored off Ensenada, Mexico, during the southbound migration. The objectives were to determine southbound migration timing and width of the migration corridor during three seasons (2003–2006). Migration timing was determined by fitting a generalized additive model to the shore counts for each season and estimating the 10, 50, and 90 percentiles of the fitted curves. To estimate abundance from shore‐based counts, a probability density function for the shore based distances was estimated by a product of a gamma distribution fit to the boat survey distance data for 2006/2007 and a half‐normal detection function using combined data of the three seasons. The parameters of the gamma distribution were corrected to account for less boat survey effort carried out 20–40 km than 0–20 km from shore. The onset of the migration off Ensenada was in late December/early January and ended around 13 February. The median date was 23–26 January for the first and third season and a week early for the second season. Boat surveys indicated a wide (20 km) migration corridor but most gray whales traveled within 9.9 km from shore. The estimated total number of whales during watch hours was 2,298 (95% CI = 1,536–4,447).     

Distribution,habitat and conservation status of desert pupfish (Cyprinodon macularius) in the Lower Colorado River Basin,Mexico

In order to better determine the currentstatus of desert pupfish populations (Cyprinodon macularius macularius) in the LowerColorado River Basin of Mexico, bimonthly fishsampling and habitat evaluations were carriedout from September 1996 to August 1997 in sixlocalities of Baja California and Sonora.Desert pupfish were collected using minnowseines and traps. Four sampling sites are inSonora, in shallow marginal habitats of theCiénega Santa Clara (Hunters' Camp, Outletof the Welton-Mohawk channel, El Doctor andFlor del Desierto) and two are in BajaCalifornia (Cerro Prieto and streams south ofCerro Prieto). The most abundant fish speciessampled was native desert pupfish (C.macularius, 59%) followed by sailfin molly(Poecilia latipinna, 19%), redbellytilapia (Tilapia cf. zilli, 10%) and western mosquito fish (Gambusiaaffinis, 7%). Significant temporalfluctuations in distribution and abundance ofdesert pupfish populations, as previouslyreported for these populations, was againdocumented. The main anthropogenic factorsaffecting distribution and abundance of desertpupfish populations in the Mexican portion ofthe Lower Colorado River Basin are progressivealteration of aquatic and riparian habitats, aswell as presence of exotic fishes that havecaused the displacement or elimination ofnative fish populations. Both habitat andpresence of the desert pupfish populations inthe study area are controlled by theperiodicity, quality and volume of dischargesinto the Mexican portion of the basin from theUnited States.     

Association between age at menarche and early-life nutritional status in rural Bangladesh

Age at menarche is associated with anthropometry in adolescence. Recently, there has been growing support for the hypothesis that timing of menarche may be set early in life but modified by changes in body size and composition in childhood. To evaluate this, a cohort of 255 girls aged <5 years recruited in 1988 were followed up in 2001 in Matlab, Bangladesh. The analysis was based on nutritional status as assessed by anthropometry and recalled age at menarche. Data were examined using lifetable techniques and the Cox regression model. The association between nutritional status indicators and age at menarche was examined in a multivariate model adjusting for potential confounding variables. Censored cases were accounted for. The median age at menarche was 15.1 years. After controlling for early-life predictors (birth size, childhood underweight, childhood stunting) it appeared that adolescent stunting stood out as the most important determinant of age at menarche. Adolescent stunting still resonates from the effect of stunting in early childhood (OR respectively 2.63 (p<0.01 CI: 1.32-5.24) and 8.47 (p<0.001 CI: 3.79-18.93) for moderately and severely stunted under-fives as compared with the reference category). Birth size was not a significant predictor of age at menarche. It is concluded that age at menarche is strongly influenced by nutritional status in adolescence, notably the level of stunting, which is in turn highly dependent on the level of stunting in early childhood. A 'late' menarche due to stunting may be detrimental for reproductive health in case of early childbearing because of the association between height and pelvic size.