AVPR1b variation and the emergence of adaptive phenotypes in Platyrrhini primates.

Platyrrhini (New World monkeys, NWm) are a group of primates characterized by behavioral and reproductive traits that are otherwise uncommon among primates, including social monogamy, direct paternal care, and twin births. As a consequence, the study of Platyrrhine primates is an invaluable tool for the discovery of the genetic repertoire underlying these taxon-specific traits. Recently, high conservation of vasopressin (AVP) sequence, in contrast with high variability of oxytocin (OXT), has been described in NWm. AVP and OXT functions are possible due to interaction with their receptors: AVPR1a, AVPR1b, AVPR2, and OXTR; and the variability in this system is associated with the traits mentioned above. Understanding the variability in the receptors is thus fundamental to understand the function and evolution of the system as a whole. Here we describe the variability of AVPR1b coding region in 20 NWm species, which is well-known to influence behavioral traits such as aggression, anxiety, and stress control in placental mammals. Our results indicate that 4% of AVPR1b sites may be under positive selection and a significant number of sites under relaxed selective constraint. Considering the known role of AVPR1b, we suggest that some of the changes described here for the Platyrrhini may be a part of the genetic repertoire connected with the complex network of neuroendocrine mechanisms of AVP-OXT system in the modulation of the HPA axis. Thus, these changes may have promoted the emergence of social behaviors such as direct paternal care in socially monogamous species that are also characterized by small body size and twin births.

Oxytocin and arginine vasopressin systems in the domestication process.

Domestication is of unquestionable importance to the technological revolution that has given rise to modern human societies. In this study, we analyzed the DNA and protein sequences of six genes of the oxytocin and arginine vasopressin systems (OXT-OXTR; AVP-AVPR1a, AVPR1b and AVPR2) in 40 placental mammals. These systems play an important role in the control of physiology and behavior. According to our analyses, neutrality does not explain the pattern of molecular evolution found in some of these genes. We observed specific sites under positive selection in AVPR1b (ω = 1.429, p = 0.001) and AVPR2 (ω= 1.49, p = 0.001), suggesting that they could be involved in behavior and physiological changes, including those related to the domestication process. Furthermore, AVPR1a, which plays a role in social behavior, is under relaxed selective constraint in domesticated species. These results provide new insights into the nature of the domestication process and its impact on the OXT-AVP system.

Progesterone Response Element Variation in the OXTR Promoter Region and Paternal Care in New World Monkeys.

Paternal care is a complex social behavior common in primate species with socially monogamous mating systems and twin births. Evolutionary causes and consequences of such behavior are not well understood, nor are their neuroendocrine and genetic bases. However, the neuropeptide oxytocin (OXT) and its receptor (OXTR) are associated with parental care in mammalian lineages. Here we investigated the interspecific variation in the number of progesterone response elements (PREs) in the OXTR promoter region of 32 primate species, correlating genetic data with behavior, social systems, and ecological/life-history parameters, while controlling for phylogeny. We verified that PREs are only present in New World monkeys and that PRE number is significantly correlated with the presence of paternal care in this branch. We suggest that PRE number could be an essential part of the genetic repertoire that allowed the emergence of taxon-specific complex social behaviors, such as paternal care in marmosets and tamarins.

A tale of agriculturalists and hunter-gatherers: Exploring the thrifty genotype hypothesis in native South Americans.

OBJECTIVES: To determine genetic differences between agriculturalist and hunter-gatherer southern Native American populations for selected metabolism-related markers and to test whether Neel's thrifty genotype hypothesis (TGH) could explain the genetic patterns observed in these populations. MATERIALS AND METHODS: 375 Native South American individuals from 17 populations were genotyped using six markers (APOE rs429358 and rs7412; APOA2 rs5082; CD36 rs3211883; TCF7L2 rs11196205; and IGF2BP2 rs11705701). Additionally, APOE genotypes from 39 individuals were obtained from the literature. AMOVA, main effects, and gene-gene interaction tests were performed. RESULTS: We observed differences in allele distribution patterns between agriculturalists and hunter-gatherers for some markers. For instance, between-groups component of genetic variance (FCT ) for APOE rs429358 showed strong differences in allelic distributions between hunter-gatherers and agriculturalists (p = 0.00196). Gene-gene interaction analysis indicated that the APOE E4/CD36 TT and APOE E4/IGF2BP2 A carrier combinations occur at a higher frequency in hunter-gatherers, but this combination is not replicated in archaic (Neanderthal and Denisovan) and ancient (Anzick, Saqqaq, Ust-Ishim, Mal'ta) hunter-gatherer individuals. DISCUSSION: A complex scenario explains the observed frequencies of the tested markers in hunter-gatherers. Different factors, such as pleotropic alleles, rainforest selective pressures, and population dynamics, may be collectively shaping the observed genetic patterns. We conclude that although TGH seems a plausible hypothesis to explain part of the data, other factors may be important in our tested populations.

Ancestry resolution of South Brazilians by forensic 165 ancestry-informative SNPs panel.

Forensic DNA phenotyping (FDP) includes biogeographic ancestry (BGA) inference and externally visible characteristics (EVCs) prediction directly from an evidential DNA sample as alternatives to provide valuable intelligence when conventional DNA profiling fails to achieve identification. In this context, the application of Massively Parallel Sequencing (MPS) methodologies, which enables simultaneous typing of multiple samples and hundreds of forensic markers, has been gradually implemented in forensic genetic casework. The Precision ID Ancestry Panel (Thermo Fisher Scientific, Waltham, USA) is a forensic multiplex assay consisting of 165 autosomal SNPs designed to provide biogeographic ancestry information. In this work, a sample of 250 individuals from Rio Grande do Sul (RS) State, southern Brazil, apportioned into four main population groups (African-, European-, Amerindian-, and Admixed-derived Gauchos), was evaluated with this panel, to assess the feasibility of this approach in a highly heterogeneous population. Forensic descriptive parameters estimated for each population group revealed that this panel has enough polymorphic and informative SNPs to be used as a supplementary instrument in forensic individual identification and kinship testing regardless of ethnicity. No statistically significant deviation from Hardy-Weinberg equilibrium was observed after Bonferroni correction. However, seven loci pairs displayed linkage disequilibrium in pairwise LD testing (p < 3.70 × 10-6). Interpopulation comparisons by FST analysis, MDS plot, and STRUCTURE analysis among the four RS population groups apart and along with 89 reference worldwide populations demonstrated that Admixed- and African-derived Gauchos present the highest levels of admixture and population stratification, whereas European- and Amerindian-derived exhibit a more homogeneous genetic conformation.

Forensic characterization of Brazilian regional populations through massive parallel sequencing of 124 SNPs included in HID ion Ampliseq Identity Panel.

Use of Massive Parallel Sequencing (MPS) techniques has been investigated by forensic community aiming introduction of such methods in routine forensic casework analyses. Interesting features presented by MPS include high-throughput, ability to simultaneous genotyping of significant number of samples and forensic markers, workflow automation, among others. Emergence of single nucleotide polymorphism (SNP) as forensic relevant markers was facilitated in this process, since concurrent typing of larger marker sets is necessary for obtaining same levels of individual discrimination provided by other marker categories. In this context, HID Ion Ampliseq Identity Panel is a commercial solution with forensic purposes comprising simultaneous analysis of 90 highly informative autosomal SNPs and 34 Y -chromosome superior clade SNPs for male lineage haplotyping. SNP typing can be obtained with smaller amplicons, and this panel was designed for efficient processing of critical or challenging forensic samples. In this work, a sample of 432 individuals from all five Brazilian geopolitical regions was evaluated with this panel, in order to access feasibility of this panel use in a national basis. Results obtained for all five regions, including forensic parameters, show that this marker set can be efficiently employed for Brazilian nationals in human identification or kinship determination applications, due to high levels of genetic discriminative information content displayed by Brazilians. Interpopulation comparison studies were executed among Brazilian regional populations and 26 worldwide populations, in order to access genetic stratification occurrence. Some levels of population structure were identified, and impact on database design was discussed. Y-chromosome haplotyping of Brazilian samples revealed high levels of European ancestry in Brazilian male lineages, and utility of haplotyping in real forensic casework is addressed. Finally, genotyping and sequencing efficiency with this panel were addressed, as an effort to appraise the adequacy of this panel use in Brazilian national forensic demands.

Oxytocin and arginine vasopressin systems in the domestication process

Abstract Domestication is of unquestionable importance to the technological revolution that has given rise to modern human societies. In this study, we analyzed the DNA and protein sequences of six genes of the oxytocin and arginine vasopressin systems (OXT-OXTR; AVP-AVPR1a, AVPR1b and AVPR2) in 40 placental mammals. These systems play an important role in the control of physiology and behavior. According to our analyses, neutrality does not explain the pattern of molecular evolution found in some of these genes. We observed specific sites under positive selection in AVPR1b (ω = 1.429, p = 0.001) and AVPR2 (ω= 1.49, p = 0.001), suggesting that they could be involved in behavior and physiological changes, including those related to the domestication process. Furthermore, AVPR1a, which plays a role in social behavior, is under relaxed selective constraint in domesticated species. These results provide new insights into the nature of the domestication process and its impact on the OXT-AVP system.