Lack of gene-language correlation due to reciprocal female but directional male admixture in Austronesians and non-Austronesians of East Timor

Y-chromosomal Status of Six Indo-European-speaking Arab Subpopulations in Chaharmahal and Bakhtiari Province, Iran

BACKGROUND

We analyzed the Y-chromosome haplogroups of six documented Arab subpopulations that accommodated separately in different counties of Chaharmahal and Bakhtiari Province but nowadays speak Indo-European language (Luri and Farsi).

METHODS

This was an outcome study conducted in 2015 to test whether there was any genetic relatedness among some Indo-European-speaking Arab subpopulation accommodated in a geographically similar region, Chaharmahal and Bakhtiari Province, Iran. Seven main Y-chromosome bi-allelic markers were genotyped in six documented Arab subpopulations. Therefore, after DNA extraction from blood samples, PCR reaction carried out by designed primers for J1-M267, J2-M172, and J-M304, I-M170, IJ-M429, F-M89 and K-M9 markers. Then PCR products after quality control on agarose gel were sequenced.

RESULTS

Most subjects (83.3%) belonged to F-M89 haplogroup. These subjects belonged to K-M9 (40%), J2-M172 (40%) and I-M170 (20%). Generally, there were at least three genetically distinct ancestors with a divergence date of about 22200 yr for I, 429000 for J and 47400 before present for K haplogroup and may show separate historical migrations of studied populations. As the most recent common ancestor (MRCA) of most of these populations, haplogroup F, lived about 40000-50000 yr ago, the data do not support a nearly close genetic relationship among all of these populations. However, there were populations with same haplogroups J2 (n=2), K (n=2), or with a closer MRCA, IJ haplogroups, among I and J2 haplogroups. Finding haplogroup I, a specific European haplogroup, among Arab populations was not expected.

CONCLUSION

Identification of various haplogroups in Arab subpopulations despite its small area and geographically conserved region of this part of Iranian plateau was unexpected.

Kinship structures create persistent channels for language transmission

Associations between genes and languages occur even with sustained migration among communities. By comparing phylogenies of genes and languages, we identify one source of this association. In traditional tribal societies, marriage customs channel language transmission. When women remain in their natal community and men disperse (matrilocality), children learn their mothers’ language, and language correlates with maternally inherited mitochondrial DNA. For the converse kinship practice (patrilocality), language instead correlates with paternally inherited Y chromosome. Kinship rules dictating postmarital residence can persist for many generations and determine population genetic structure at the community scale. The long-term association of languages with genetic clades created by kinship systems provides information about language transmission, and about the structure and persistence of social groups.

Languages are transmitted through channels created by kinship systems. Given sufficient time, these kinship channels can change the genetic and linguistic structure of populations. In traditional societies of eastern Indonesia, finely resolved cophylogenies of languages and genes reveal persistent movements between stable speech communities facilitated by kinship rules. When multiple languages are present in a region and postmarital residence rules encourage sustained directional movement between speech communities, then languages should be channeled along uniparental lines. We find strong evidence for this pattern in 982 individuals from 25 villages on two adjacent islands, where different kinship rules have been followed. Core groups of close relatives have stayed together for generations, while remaining in contact with, and marrying into, surrounding groups. Over time, these kinship systems shaped their gene and language phylogenies: Consistently following a postmarital residence rule turned social communities into speech communities.

Growth curves and the international standard: How children's growth reflects challenging conditions in rural Timor-Leste

OBJECTIVES

Population-specific growth references are important in understanding local growth variation, especially in developing countries where child growth is poor and the need for effective health interventions is high. In this article, we use mixed longitudinal data to calculate the first growth curves for rural East Timorese children to identify where, during development, deviation from the international standards occurs.

MATERIALS AND METHODS

Over an eight-year period, 1,245 children from two ecologically distinct rural areas of Timor-Leste were measured a total of 4,904 times. We compared growth to the World Health Organization (WHO) standards using z-scores, and modeled height and weight velocity using the SuperImposition by Translation And Rotation (SITAR) method. Using the Generalized Additive Model for Location, Scale and Shape (GAMLSS) method, we created the first growth curves for rural Timorese children for height, weight and body mass index (BMI).

RESULTS

Relative to the WHO standards, children show early-life growth faltering, and stunting throughout childhood and adolescence. The median height and weight for this population tracks below the WHO fifth centile. Males have poorer growth than females in both z-BMI (p = .001) and z-height-for-age (p = .018) and, unlike females, continue to grow into adulthood.

DISCUSSION

This is the most comprehensive investigation to date of rural Timorese children's growth, and the growth curves created may potentially be used to identify future secular trends in growth as the country develops. We show significant deviation from the international standard that becomes most pronounced at adolescence, similar to the growth of other Asian populations. Males and females show different growth responses to challenging conditions in this population.