Does Breastfeeding Protect Against Pediatric Overweight? Analysis of Longitudinal Data From the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System

Objective. To examine whether increasing duration of breastfeeding is associated with a lower risk of overweight in a low-income population of 4-yearolds in the United States. Methods. Visit data were linked to determine prospectively the duration of breastfeeding (up to 2 years of age) and weight status at 4 years of age. Overweight among 4-year-old children was defined as a body mass index (BMI)-for-age at or above the 95th percentile based on the 2000 Centers for Disease Control and Prevention growth charts. Logistic regression was performed, controlling for gender, race/ethnicity, and birth weight. In a subset of states, links to maternal pregnancy records also permitted regression analysis controlling for mother’s age, education, prepregnancy BMI, weight gain during pregnancy, and postpartum smoking. Data from the Pediatric Nutrition Surveillance System, which extracts breastfeeding, height, and weight data from child visits to public health programs, were analyzed. In 7 states, data were linked to Pregnancy Nutrition Surveillance System data. A total of 177 304 children up to 60 months of age were included in our final pediatric-only analysis, and 12 587 were included in the pregnancy-pediatric linked analysis. Results. The duration of breastfeeding showed a dose-response, protective relationship with the risk of overweight only among non-Hispanic whites; no significant association was found among non-Hispanic blacks or Hispanics. Among non-Hispanic whites, the adjusted odds ratio of overweight by breastfeeding for 6 to 12 months versus never breastfeeding was 0.70 (95% confidence interval: 0.50–0.99) and for \u3e12 months versus never was 0.49 (95% confidence interval: 0.25– 0.95). Breastfeeding for any duration was also protective against underweight (BMI-for-age below the 5th percentile). Conclusion. Prolonged breastfeeding is associated with a reduced risk of overweight among non-Hispanic white children. Breastfeeding longer than 6 months provides health benefits to children well beyond the period of breastfeeding

Four species linked by three hybrid zones: two instances of repeated hybridization in one species group (Genus Liolaemus)

Hybridization is an evolutionary process that can generate diverse outcomes, such as reinforcing species boundaries, generating new species, or facilitating the introgression of locally-adapted alleles into new genomic backgrounds. Liolaemus is a highly diverse clade of South American lizards with ∼260 species and as many as ten new species are described each year. Previous Liolaemus studies have detected gene flow and introgression among species using phylogenetic network methods and/or through comparisons of nuclear and mitochondrial DNA patterns, yet no study has systematically studied hybrid zones between Liolaemus species. Here, we compared three hybrid zones between four species in the Liolaemus fitzingerii group of lizards in Central Argentina where two species, L. melanops and L. xanthoviridis, each hybridize withtwo other species (L. shehuen and L. fitzingerii). We sampled three transects that were each ∼120 km in length and sequenced both mitochondrial and genome-wide SNP data for 267 individuals. In our analyses of nuclear DNA, we also compared bi-allelic SNPs to phased alleles (50 bp RAD loci). Population structure analyses confirmed that boundaries separating species are sharp, and all clines are <65 km wide. Cline center estimates were consistent between SNPs and phased alleles, but cline width estimates were significantly different with the SNPs producing wider estimates. The mitochondrial clines are narrower and shifted 4?20 km southward in comparison to the nuclear clines in all three hybrid zones, indicating that either each of the species has sex-biased dispersal (males northward or females southward), the population densities are unequal, or that the hybrid zones are moving north over time. These comparisonsindicate that some patterns of hybridization are similar across hybrid zones (mtDNA clines all narrower and shifted to the south), whereas cline width is variable. Hybridization in the L. fitzingerii group is common and geographically localized; further studies are needed to investigate whether hybrid zones act as hard species boundaries or promoters ofspeciation through processes such as reinforcement. Nonetheless, this study provides insights into both biotic and abiotic mechanisms helping to maintain species boundaries within the speciose Liolaemus system.Fil: Grummer, Jared A.. University of Washington; Estados UnidosFil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Morando, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Leaché, Adam D.. University of Washington; Estados Unido

Biosystematic Study of the Relationship of Nama Hispidum and Nama Stevensii

This study is concerned with the reproductive biology and morphological relationship between Nama hispidumand Nama stevensii. In order to better understand this relationship, a more intense study was needed.Botan

Fish growth changes over time in a Midwestern USA lake

Growth of Walleye Sander vitreus, Yellow Bass Morone mississippiensis, Common Carp Cyprinus carpio, and Black Bullhead Ameiurus melas was assessed in Clear Lake, Iowa, USA, over several decades and in relation to environmental variables. Growth of Common Carp was positively correlated with phytoplankton concentration. Recent Black Bullhead growth was faster than in the 1950s and 1990s, which may be a consequence of their recent decline in abundance. Growth of Common Carp and Yellow Bass was faster in the 1940s than in more recent time periods. Relative to their entire range, Common Carp first year growth was below average whereas length at later ages was above average. Walleye relative growth showed a similar pattern. The large changes in growth over several decades suggest that as the Clear Lake ecosystem continues to change, growth rates of its important fish species are also likely to continue changing

Incidence of Obesity Among Young US Children Living in Low-Income Families, 2008–2011

OBJECTIVE: To examine the incidence and reverse of obesity among young low-income children and variations across population subgroups. METHODS: We included 1.2 million participants in federally funded child health and nutrition programs who were 0 to 23 months old in 2008 and were followed up 24 to 35 months later in 2010–2011. Weight and height were measured. Obesity at baseline was defined as gender-specific weight-for-length \u3e/=95th percentile on the 2000 Centers for Disease Control and Prevention growth charts. Obesity at follow-up was defined as gender-specific BMI-for-age \u3e/=95th percentile. We used a multivariable log-binomial model to estimate relative risk of obesity adjusting for gender, baseline age, race/ethnicity, duration of follow-up, and baseline weight-for-length percentile. RESULTS: The incidence of obesity was 11.0% after the follow-up period. The incidence was significantly higher among boys versus girls and higher among children aged 0 to 11 months at baseline versus those older. Compared with non-Hispanic whites, the risk of obesity was 35% higher among Hispanics and 49% higher among American Indians (AIs)/Alaska Natives (ANs), but 8% lower among non-Hispanic African Americans. Among children who were obese at baseline, 36.5% remained obese and 63.5% were nonobese at follow-up. The proportion of reversing of obesity was significantly lower among Hispanics and AIs/ANs than that among other racial/ethnic groups. CONCLUSIONS: The high incidence underscores the importance of earlylife obesity prevention in multiple settings for low-income children and their families. The variations within population subgroups suggest that culturally appropriate intervention efforts should be focused on Hispanics and AIs/ANs

Phylogenomic evidence for a recent and rapid radiation of lizards in the Patagonian Liolaemus fitzingerii species group

Rapid evolutionary radiations are difficult to resolve because divergence events are nearly synchronous and gene flow among nascent species can be high, resulting in a phylogenetic “bush”. Large datasets composed of sequence loci from across the genome can potentially help resolve some of these difficult phylogenetic problems. A suitable test case is the Liolaemus fitzingerii species group of lizards, which includes twelve species that are broadly distributed in Argentinean Patagonia. The species in the group have had a complex evolutionary history that has led to high morphological variation and unstable taxonomy. We generated a sequence capture dataset for 28 ingroup individuals of 580 nuclear loci, alongside a mitogenomic dataset, to infer phylogenetic relationships among species in this group. Relationships among species were generally weakly supported with the nuclear data, and along with an inferred age of ∼2.6 million years old, indicate either rapid evolution, hybridization, incomplete lineage sorting, non-informative data, or a combination thereof. We inferred a signal of mito-nuclear discordance, indicating potential hybridization between L. melanops and L. martorii, and phylogenetic network analyses provided support for 5 reticulation events among species. Phasing the nuclear loci did not provide additional insight into relationships or suspected patterns of hybridization. Only one clade, composed of L. camarones, L. fitzingerii, and L. xanthoviridis was recovered across all analyses. Genomic datasets provide molecular systematists with new opportunities to resolve difficult phylogenetic problems, yet the lack of phylogenetic resolution in Patagonian Liolaemus is biologically meaningful and indicative of a recent and rapid evolutionary radiation. The phylogenetic relationships of the Liolaemus fitzingerii group may be best modeled as a reticulated network instead of a bifurcating phylogeny.Fil: Grummer, Jared A.. University of Washington; Estados UnidosFil: Morando, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Sites, Jack W.. University Brigham Young; Estados UnidosFil: Leaché, Adam D.. University of Washington; Estados Unido