PubMed · 11632180
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C Bravo. 1974. [Not Available].. https://pubmed.ncbi.nlm.nih.gov/11632180/
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Species delimitation in the South American genus Polylepis is notoriously challenging due to high morphological similarity and phenotypic plasticity, likely driven by hybridization and gene flow. Previous phylogenetic studies suggested that genetic structure aligns more strongly with geography than with taxonomy, questioning existing species concepts and hampering conservation efforts. We used double-digest RAD sequencing (ddRADseq) to generate genome-wide SNP data for 11 Polylepis species sampled across multiple localities in Bolivia and Ecuador. Population genetic analyses, phylogenetic inference, and network approaches were combined to assess whether genetic structure aligns more closely with taxonomy or geography. Morphologically defined species formed largely cohesive genetic lineages across regions, with species identity explaining substantially more genetic variation than locality. While localized admixture and reticulation were detected among closely related taxa, widespread species showed strong genetic cohesion and clear separation from congeners. Our results indicate that the sampled Polylepis species from Bolivia and Ecuador maintain distinct genetic identities despite localized signals consistent with gene flow. This genome-wide support for current taxonomy highlights Polylepis as a valuable model for studying speciation under gene flow and indicates that multiple geographic sampling will be essential in reconstructing a robust phylogeny of the genus, with important implications for conservation planning in Andean montane forests.
BACKGROUND: Recent ecological research from Latin America has shown that infant health could be promoted through exclusive breastfeeding in infants aged 0-3 months and partial breastfeeding throughout the remainder of infancy. METHODS: In a cross-sectional study in 1995, the author interviewed 518 mothers with infants leq; 1 year in La Paz, Bolivia, to describe the breastfeeding pattern and its determinants including socio-economic, religious and ethnic background. RESULTS: The rate of any breastfeeding remained above 85% during the first year. Exclusive breastfeeding rates fell from 89% at one week of age to 45% as early as one month of age, and then gradually declined to 20-25% in 6-month-old infants. The overall exclusive breastfeeding rate in infants < 4 months was 46% (n = 246). The use of prelacteal feeds (p < 0.0001, n = 436), not feeding the infant colostrum (p = 0.0008, n = 436), and Latin ethnicity (p = 0.0091, n = 436) were associated with a shorter duration of exclusive breastfeeding. Rural mothers were four times more likely to discard the colostrum than urban mothers (p = 0.0110, n = 501). Actual exclusive breastfeeding duration was shorter than what the mothers reported to be the ideal duration of exclusive breastfeeding for the infant. CONCLUSIONS: The rate of exclusive breastfeeding in Bolivian infants fell rapidly during the first months of life. Avoidance of prelacteal feeding and use of colostrum were associated with improved breastfeeding patterns.
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