Papers by Nicolas Montalva
Frontiers in Genetics, 2022
Human Nature
Globally, mortality and fertility rates generally fall as resource abundance increases. This patt... more Globally, mortality and fertility rates generally fall as resource abundance increases. This pattern represents an evolutionary paradox insofar as resource-rich ecological contexts can support higher numbers of offspring, a component of biological fitness. This paradox has not been resolved, in part because the relationships between fertility, life history strategies, reproductive behavior, and socioeconomic conditions are complex and cultural-historically contingent. We aim to understand how we might make sense of this paradox in the specific context of late-twentieth-century, mid–demographic transition Chile. We use distribution-specific generalized linear models to analyze associations between fertility-related life-history traits—number of offspring, ages at first and last reproduction, average interbirth interval, and average number of live births per reproductive span year—and socioeconomic position (SEP) using data from a cohort of 6,802 Chilean women born between 1961 and 19...
International Journal of Environmental Research and Public Health
Background: Despite its enormous health and social burden, there are limited published studies de... more Background: Despite its enormous health and social burden, there are limited published studies describing the epidemiology of violent deaths in Chile. We described violent mortality rate trends in Chile between 2001 and 2018, its current spatial distribution and ecological level correlates. Methods: A population-based study using publicly accessible data. We calculated age-adjusted mortality rates per 100,000 persons for sex, age, intention, and mechanism of death. Next, we used linear regression to estimate time trends for sex and intention. We then employed hierarchical Poisson analyses to model the spatial distribution across 345 municipalities and the influence of six ecological level variables. Results: The average rate of violent death in Chile between 2001 and 2018 was 15.9 per 100,000 people, with the majority (70.3%) of these attributed to suicide. Suffocation was the most common mechanism of death for suicide (82.3%) and cut/pierce for homicide (43.1%), followed by firearm...
Estudios Atacameños, 2019
Annals of human genetics, Jan 27, 2018
The genetic trait of lactase persistence (LP) evolved as an adaptation to milking pastoralism in ... more The genetic trait of lactase persistence (LP) evolved as an adaptation to milking pastoralism in the Old World and is a well-known example of positive natural selection in humans. However, the specific mechanisms conferring this selective advantage are unknown. To understand the relationship between milk drinking, LP, growth, reproduction, and survival, communities of the Coquimbo Region in Chile, with recent adoption of milking agropastoralism, were used as a model population. DNA samples and data on stature, reproduction, and diet were collected from 451 participants. Lactose tolerance tests were done on 41 of them. The European -13,910*T (rs4988235) was the only LP causative variant found, showing strong association (99.6%) with LP phenotype. Models of associations of inferred LP status and milk consumption, with fertility, mortality, height, and weight were adjusted with measures of ancestry and relatedness to control for population structure. Although we found no statistically ...
Human genetics, Nov 23, 2017
The genetic trait of lactase persistence (LP) is associated with at least five independent functi... more The genetic trait of lactase persistence (LP) is associated with at least five independent functional single nucleotide variants in a regulatory region about 14 kb upstream of the lactase gene [-13910*T (rs4988235), -13907*G (rs41525747), -13915*G (rs41380347), -14009*G (rs869051967) and -14010*C (rs145946881)]. These alleles have been inferred to have spread recently and present-day frequencies have been attributed to positive selection for the ability of adult humans to digest lactose without risk of symptoms of lactose intolerance. One of the inferential approaches used to estimate the level of past selection has been to determine the extent of haplotype homozygosity (EHH) of the sequence surrounding the SNP of interest. We report here new data on the frequencies of the known LP alleles in the 'Old World' and their haplotype lineages. We examine and confirm EHH of each of the LP alleles in relation to their distinct lineages, but also show marked EHH for one of the older ...
American Journal of Human Biology, 2015
Objectives: Lactase persistence (LP) is a genetic trait that has been studied among different cou... more Objectives: Lactase persistence (LP) is a genetic trait that has been studied among different countries and ethnic groups. In Latin America, the frequencies of this trait have been shown to vary according to the degree of admixture of the populations. The objective of this study is to better understand the relationship between this genetic trait and dairy intake in a multiethnic context through a synthesis of studies conducted in four regions of Chile. Methods: Genotypes frequencies for the SNP LCT-13910C>T (rs4988235) and frequency of dairy consumption were obtained from four populations: Polynesians from Easter Island (Rapanui); Amerindians (Mapuche) and Mestizos from the Araucan ıa region; urban Mestizos from Santiago; and rural Mestizos from the Coquimbo region. Genetic differentiation and association between milk consumption and genotype frequencies were estimated. Results: Genetic differentiation between Native and Mestizo populations was significant; the LP frequency in Mapuche and Rapanui was 10% and 25%, respectively, whereas among the Mestizos, LP frequency was near 40%. Dairy intake was below the nutritional recommendations for the four groups, and extremely below recommendations among the indigenous populations. Association between milk intake and LP was found in Santiago and Rapanui populations. Conclusions: Although the frequency of LP varies among the populations according to their degree of admixture, dairy consumption was very low across the populations. Given that the association between milk consumption and expected phenotype was found only in two of the populations analyzed, it seems that lactase non-persistence (LNP) is not the only cause for dairy avoidance. Thus, it is suggested that SES and cultural preferences are likely affecting dairy consumption. Am.
Human genetics, Jan 9, 2015
The genetic trait of lactase persistence is attributable to allelic variants in an enhancer regio... more The genetic trait of lactase persistence is attributable to allelic variants in an enhancer region upstream of the lactase gene, LCT. To date, five different functional alleles, -13910*T, -13907*G, -13915*G, -14009*G and -14010*C, have been identified. The co-occurrence of several of these alleles in Ethiopian lactose digesters leads to a pattern of sequence diversity characteristic of a 'soft selective sweep'. Here we hypothesise that throughout Africa, where multiple functional alleles co-exist, the enhancer diversity will be greater in groups who are traditional milk drinkers than in non-milk drinkers, as the result of this sort of parallel selection. Samples from 23 distinct groups from 10 different countries were examined. Each group was classified 'Yes 'or…
Scientific Reports, 2014
Milk is a major food of global economic importance, and its consumption is regarded as a classic ... more Milk is a major food of global economic importance, and its consumption is regarded as a classic example of gene-culture evolution. Humans have exploited animal milk as a food resource for at least 8500 years, but the origins, spread, and scale of dairying remain poorly understood. Indirect lines of evidence, such as lipid isotopic ratios of pottery residues, faunal mortality profiles, and lactase persistence allele frequencies, provide a partial picture of this process; however, in order to understand how, where, and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their dairy livestock. Here we report the first direct evidence of milk consumption, the whey protein b-lactoglobulin (BLG), preserved in human dental calculus from the Bronze Age (ca. 3000 BCE) to the present day. Using protein tandem mass spectrometry, we demonstrate that BLG is a species-specific biomarker of dairy consumption, and we identify individuals consuming cattle, sheep, and goat milk products in the archaeological record. We then apply this method to human dental calculus from Greenland's medieval Norse colonies, and report a decline of this biomarker leading up to the abandonment of the Norse Greenland colonies in the 15 th century CE. M ilk is a major nutritional resource. In addition to being a source of clean liquid (milk is 80-90% water), milk solids contain approximately 25-55% sugar (lactose), 25-45% fat, and 5-35% protein (caseins and whey proteins), as well as calcium, potassium, and B-vitamins 1. Adoption of animal milk consumption by humans typically requires behavioral adaptations, such as culturing and curdling techniques, to remove or reduce the lactose content of milk in order to make dairy products digestible after infancy. Additionally, populations with long pastoralist traditions in Europe and India, East Africa, and the Arabian peninsula have also independently evolved lactase persistence (LP), a genetic adaptation in the regulation of the lactase gene (LCT) that allows continued adult digestion of milk 2,3 (Fig. 1). LP is hailed as one of the clearest examples of gene-culture co-evolution in humans 4 , yet many fundamental aspects of its evolution remain unknown 5-9 and the socioeconomic context and scale of prehistoric and historic dairying are only poorly understood. The ability to directly identify milk consumption patterns in past populations would thus advance understanding of human dietary ecology, evolution, and cultural agency. However, previous attempts to directly measure milk consumption using bone calcium isotopes have proven unsuccessful 10. Other milk biomarkers offer only indirect lines of evidence. For example, isotopic inference of milk lipids from pottery residues 11 is the most widely used approach to identify dairying, but this method cannot discriminate species of origin, and reuse of communal vessels and exploitation of cervid adipose tissue 12 both pose further challenges to interpretation. Milk proteins have also been recovered from food residues 13-15 , but such finds are exceptional and rare, and
Estudios Atacameños, 2019
La noción de un giro único de la modernidad occidental en las formas de articular la relación ent... more La noción de un giro único de la modernidad occidental en las formas de articular la relación entre política y vida biológica ha traído la idea de un paisaje político dominado por discursos de autoridad promovidos por un conjunto de disciplinas, técnicas y tecnologías biológicas. La emergencia de un concepto de ciudadanías biológicas parece una herramienta analítica requerida para las ciencias sociales. Este artículo pone limitaciones al alcance de una herramienta analítica de este tipo. Basado en experiencias con pastores de cabras trashumantes del Norte Chico chileno y grupos urbanos que abogan por una dieta libre de leche, la biociudadanía no parece ser un buen descriptor de la agencia política entre las comunidades de pastores de cabras, e incluso cuando parece
serlo, la articulación biológica de la ciudadanía se muestra como el producto artificial de un proceso de fetichización por medio de un recurso de naturalización que llamamos atavismo. Discutimos que un proceso similar afecta al concepto mismo de biopolítica, fetichizado a través de la idea etnocéntrica de una singularidad especial de la modernidad occidental, la cual inhibe a las ciencias sociales de cualquier meta orientada a entender las sociedades y priva a los ciudadanos de los medios para cambiarlas.
The genetic trait of lactase persistence (LP) evolved as an adaptation to milking pas-toralism in... more The genetic trait of lactase persistence (LP) evolved as an adaptation to milking pas-toralism in the Old World and is a well-known example of positive natural selection in humans. However, the specific mechanisms conferring this selective advantage are unknown. To understand the relationship between milk drinking, LP, growth, reproduction , and survival, communities of the Coquimbo Region in Chile, with recent adoption of milking agropastoralism, were used as a model population. DNA samples and data on stature, reproduction, and diet were collected from 451 participants. Lactose tolerance tests were done on 41 of them. The European −13,910*T (rs4988235) was the only LP causative variant found, showing strong association (99.6%) with LP phenotype. Models of associations of inferred LP status and milk consumption, with fertility, mortality, height, and weight were adjusted with measures of ancestry and related-ness to control for population structure. Although we found no statistically significant effect of LP on fertility, a significant effect (P = 0.002) was observed of LP on body mass index (BMI) in males and of BMI on fertility (P = 0.003). These results fail to support a causal relationship between LP and fertility yet suggest the idea of a nutritional advantage of LP. Furthermore, the proportion of European ancestry around the genetic region of −13,910*T is significantly higher (P = 0.008) than the proportion of European ancestry genome-wide, providing evidence of recent positive selection since European–Amerindian admixture. This signature was absent in nonpastoralist Latin American populations, supporting the hypothesis of specific adaptation to milking agropastoralism in the Coquimbo communities.
homozygosity (EHH) of the sequence surrounding the SNP of interest. We report here new data on th... more homozygosity (EHH) of the sequence surrounding the SNP of interest. We report here new data on the frequencies of the known LP alleles in the 'Old World' and their haplotype lineages. We examine and confirm EHH of each of the LP alleles in relation to their distinct lineages, but also show marked EHH for one of the older haplotypes that does not carry any of the five LP alleles. The region of EHH of this (B) haplotype exactly coincides with a region of suppressed recombination that is detectable in families as well as in population data, and the results show how such suppression may have exaggerated haplotype-based measures of past selection.
almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The o... more almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a northeast to southwest decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however, the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection , the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition.
almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The o... more almost entirely accounted for by the Afro-Asiatic language speaking peoples of east Africa. The other groups, including the 'Nilo-Saharan language speaking' milk-drinkers, show lower frequencies of LP and lower diversity, and there was a northeast to southwest decline in overall diversity. Amongst the Afro-Asiatic (Cushitic) language speaking Oromo, however, the geographic cline was not evident and the southern pastoralist Borana showed much higher LP frequency and enhancer diversity than the other groups. Together these results reflect the effects of parallel selection , the stochastic processes of the occurrence and spread of the mutations, and time depth of milk drinking tradition.
Human genetics, Jan 9, 2015
The genetic trait of lactase persistence is attributable to allelic variants in an enhancer regio... more The genetic trait of lactase persistence is attributable to allelic variants in an enhancer region upstream of the lactase gene, LCT. To date, five different functional alleles, -13910*T, -13907*G, -13915*G, -14009*G and -14010*C, have been identified. The co-occurrence of several of these alleles in Ethiopian lactose digesters leads to a pattern of sequence diversity characteristic of a 'soft selective sweep'. Here we hypothesise that throughout Africa, where multiple functional alleles co-exist, the enhancer diversity will be greater in groups who are traditional milk drinkers than in non-milk drinkers, as the result of this sort of parallel selection. Samples from 23 distinct groups from 10 different countries were examined. Each group was classified 'Yes 'or 'No' for milk-drinking, and ethnicity, language spoken and geographic location were recorded. Predicted lactase persistence frequency and enhancer diversity were, as hypothesised, higher in the milk d...
Milk is a major food of global economic importance, and its consumption is regarded as a classi... more Milk is a major food of global economic importance, and its consumption is regarded as a classic example of gene-culture evolution. Humans have exploited animal milk as a food resource for at least 8500 years, but the origins, spread, and scale of dairying remain poorly understood. Indirect lines of evidence, such as lipid isotopic ratios of pottery residues, faunal mortality profiles, and lactase persistence allele frequencies, provide a partial picture of this process; however, in order to understand how, where, and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their dairy livestock. Here we report the first direct evidence of milk consumption, the whey protein β-lactoglobulin (BLG), preserved in human dental calculus from the Bronze Age (ca. 3000 BCE) to the present day. Using protein tandem mass spectrometry, we demonstrate that BLG is a species-specific biomarker of dairy consumption, and we identify individuals consuming cattle, sheep, and goat milk products in the archaeological record. We then apply this method to human dental calculus from Greenland's medieval Norse colonies, and report a decline of this biomarker leading up to the abandonment of the Norse Greenland colonies in the 15th century CE.
Subject terms: Archaeology
Proteomics
Zoology
Biomarkers
Objectives: Lactase persistence (LP) is a genetic trait that has been studied among different cou... more Objectives: Lactase persistence (LP) is a genetic trait that has been studied among different countries and ethnic
groups. In Latin America, the frequencies of this trait have been shown to vary according to the degree of admixture of
the populations. The objective of this study is to better understand the relationship between this genetic trait and dairy
intake in a multiethnic context through a synthesis of studies conducted in four regions of Chile.
Methods: Genotypes frequencies for the SNP LCT-13910C>T (rs4988235) and frequency of dairy consumption were
obtained from four populations: Polynesians from Easter Island (Rapanui); Amerindians (Mapuche) and Mestizos from
the Araucanıa region; urban Mestizos from Santiago; and rural Mestizos from the Coquimbo region. Genetic differentiation
and association between milk consumption and genotype frequencies were estimated.
Results: Genetic differentiation between Native and Mestizo populations was significant; the LP frequency in
Mapuche and Rapanui was 10% and 25%, respectively, whereas among the Mestizos, LP frequency was near 40%.
Dairy intake was below the nutritional recommendations for the four groups, and extremely below recommendations
among the indigenous populations. Association between milk intake and LP was found in Santiago and Rapanui
populations.
Conclusions: Although the frequency of LP varies among the populations according to their degree of admixture,
dairy consumption was very low across the populations. Given that the association between milk consumption and
expected phenotype was found only in two of the populations analyzed, it seems that lactase non-persistence (LNP) is
not the only cause for dairy avoidance. Thus, it is suggested that SES and cultural preferences are likely affecting dairy
consumption. Am. J. Hum. Biol. 00:000–000, 2015.
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Papers by Nicolas Montalva
serlo, la articulación biológica de la ciudadanía se muestra como el producto artificial de un proceso de fetichización por medio de un recurso de naturalización que llamamos atavismo. Discutimos que un proceso similar afecta al concepto mismo de biopolítica, fetichizado a través de la idea etnocéntrica de una singularidad especial de la modernidad occidental, la cual inhibe a las ciencias sociales de cualquier meta orientada a entender las sociedades y priva a los ciudadanos de los medios para cambiarlas.
Subject terms: Archaeology
Proteomics
Zoology
Biomarkers
groups. In Latin America, the frequencies of this trait have been shown to vary according to the degree of admixture of
the populations. The objective of this study is to better understand the relationship between this genetic trait and dairy
intake in a multiethnic context through a synthesis of studies conducted in four regions of Chile.
Methods: Genotypes frequencies for the SNP LCT-13910C>T (rs4988235) and frequency of dairy consumption were
obtained from four populations: Polynesians from Easter Island (Rapanui); Amerindians (Mapuche) and Mestizos from
the Araucanıa region; urban Mestizos from Santiago; and rural Mestizos from the Coquimbo region. Genetic differentiation
and association between milk consumption and genotype frequencies were estimated.
Results: Genetic differentiation between Native and Mestizo populations was significant; the LP frequency in
Mapuche and Rapanui was 10% and 25%, respectively, whereas among the Mestizos, LP frequency was near 40%.
Dairy intake was below the nutritional recommendations for the four groups, and extremely below recommendations
among the indigenous populations. Association between milk intake and LP was found in Santiago and Rapanui
populations.
Conclusions: Although the frequency of LP varies among the populations according to their degree of admixture,
dairy consumption was very low across the populations. Given that the association between milk consumption and
expected phenotype was found only in two of the populations analyzed, it seems that lactase non-persistence (LNP) is
not the only cause for dairy avoidance. Thus, it is suggested that SES and cultural preferences are likely affecting dairy
consumption. Am. J. Hum. Biol. 00:000–000, 2015.
serlo, la articulación biológica de la ciudadanía se muestra como el producto artificial de un proceso de fetichización por medio de un recurso de naturalización que llamamos atavismo. Discutimos que un proceso similar afecta al concepto mismo de biopolítica, fetichizado a través de la idea etnocéntrica de una singularidad especial de la modernidad occidental, la cual inhibe a las ciencias sociales de cualquier meta orientada a entender las sociedades y priva a los ciudadanos de los medios para cambiarlas.
Subject terms: Archaeology
Proteomics
Zoology
Biomarkers
groups. In Latin America, the frequencies of this trait have been shown to vary according to the degree of admixture of
the populations. The objective of this study is to better understand the relationship between this genetic trait and dairy
intake in a multiethnic context through a synthesis of studies conducted in four regions of Chile.
Methods: Genotypes frequencies for the SNP LCT-13910C>T (rs4988235) and frequency of dairy consumption were
obtained from four populations: Polynesians from Easter Island (Rapanui); Amerindians (Mapuche) and Mestizos from
the Araucanıa region; urban Mestizos from Santiago; and rural Mestizos from the Coquimbo region. Genetic differentiation
and association between milk consumption and genotype frequencies were estimated.
Results: Genetic differentiation between Native and Mestizo populations was significant; the LP frequency in
Mapuche and Rapanui was 10% and 25%, respectively, whereas among the Mestizos, LP frequency was near 40%.
Dairy intake was below the nutritional recommendations for the four groups, and extremely below recommendations
among the indigenous populations. Association between milk intake and LP was found in Santiago and Rapanui
populations.
Conclusions: Although the frequency of LP varies among the populations according to their degree of admixture,
dairy consumption was very low across the populations. Given that the association between milk consumption and
expected phenotype was found only in two of the populations analyzed, it seems that lactase non-persistence (LNP) is
not the only cause for dairy avoidance. Thus, it is suggested that SES and cultural preferences are likely affecting dairy
consumption. Am. J. Hum. Biol. 00:000–000, 2015.