Nasal Coarticulation and Prosody in Kakataibo.

This paper presents the first phonetic description of the patterns of nasal coarticulation in Kakataibo. While closely related Panoan languages have been described as having anticipatory nasal coarticulation in VN sequences, there are only a few reports of other types of nasal coarticulation. Based on a detailed investigation of the aerodynamic properties of nasality, we account for the full variety of nasal coarticulation patterns in Kakataibo and discuss their interaction with prosody. This paper shows that nasal coarticulation occurs in all contexts in which there is vowel-nasal contiguity, although the amount and patterns of nasal coarticulation are dependent on the directionality of the process, the presence or absence of a syllable boundary and stress.

Y-chromosome diversity in Native Mexicans reveals continental transition of genetic structure in the Americas.

The genetic characterization of Native Mexicans is important to understand multiethnic based features influencing the medical genetics of present Mexican populations, as well as to the reconstruct the peopling of the Americas. We describe the Y-chromosome genetic diversity of 197 Native Mexicans from 11 populations and 1,044 individuals from 44 Native American populations after combining with publicly available data. We found extensive heterogeneity among Native Mexican populations and ample segregation of Q-M242* (46%) and Q-M3 (54%) haplogroups within Mexico. The northernmost sampled populations falling outside Mesoamerica (Pima and Tarahumara) showed a clear differentiation with respect to the other populations, which is in agreement with previous results from mtDNA lineages. However, our results point toward a complex genetic makeup of Native Mexicans whose maternal and paternal lineages reveal different narratives of their population history, with sex-biased continental contributions and different admixture proportions. At a continental scale, we found that Arctic populations and the northernmost groups from North America cluster together, but we did not find a clear differentiation within Mesoamerica and the rest of the continent, which coupled with the fact that the majority of individuals from Central and South American samples are restricted to the Q-M3 branch, supports the notion that most Native Americans from Mesoamerica southwards are descendants from a single wave of migration. This observation is compatible with the idea that present day Mexico might have constituted an area of transition in the diversification of paternal lineages during the colonization of the Americas.

Acoustic and electroglottographic analyses of nonpathological, nonmodal phonation.

Languages where phonation type and tone are contrastive make use of extremely fine and controlled actions of laryngeal structures; hence, there is little opportunity to variation in either phonation or pitch. Nonetheless, many American Indian languages have contrastive nonmodal phonation, which, moreover, is subject to a great deal of variation. There are a few studies addressing the phonetics of nonmodal phonation in American Indian languages, and little is known about the phonetics/phonology interface of laryngeal features within the sound patterns of these languages. This article aims to contribute to the knowledge of nonmodal phonation through the detailed study of the phenomenon in Yalálag Zapotec (YZ) and American Indian language. A series of spectral and electrophysiological analyses contribute to the description of YZ nonmodal phonation and its variability across gender. It is argued that the temporal patterns in realization of laryngealization are a property of YZ speaker's grammar.

Linguistic and maternal genetic diversity are not correlated in Native Mexicans.

Mesoamerica, defined as the broad linguistic and cultural area from middle southern Mexico to Costa Rica, might have played a pivotal role during the colonization of the American continent. The Mesoamerican isthmus has constituted an important geographic barrier that has severely restricted gene flow between North and South America in pre-historical times. Although the Native American component has been already described in admixed Mexican populations, few studies have been carried out in native Mexican populations. In this study, we present mitochondrial DNA (mtDNA) sequence data for the first hypervariable region (HVR-I) in 477 unrelated individuals belonging to 11 different native populations from Mexico. Almost all of the Native Mexican mtDNAs could be classified into the four pan-Amerindian haplogroups (A2, B2, C1, and D1); only two of them could be allocated to the rare Native American lineage D4h3. Their haplogroup phylogenies are clearly star-like, as expected from relatively young populations that have experienced diverse episodes of genetic drift (e.g., extensive isolation, genetic drift, and founder effects) and posterior population expansions. In agreement with this observation, Native Mexican populations show a high degree of heterogeneity in their patterns of haplogroup frequencies. Haplogroup X2a was absent in our samples, supporting previous observations where this clade was only detected in the American northernmost areas. The search for identical sequences in the American continent shows that, although Native Mexican populations seem to show a closer relationship to North American populations, they cannot be related to a single geographical region within the continent. Finally, we did not find significant population structure in the maternal lineages when considering the four main and distinct linguistic groups represented in our Mexican samples (Oto-Manguean, Uto-Aztecan, Tarascan, and Mayan), suggesting that genetic divergence predates linguistic diversification in Mexico.