Understanding how an amphicarpic species with a mixed mating system responds to fire: a population genetic approach.

Amphicarpic plants produce both above-ground and below-ground seeds. Because below-ground seeds are protected in the soil and may maintain viability when above-ground conditions are stressful, they were proposed as an adaptation to recolonize a site after disturbance. However, whether below-ground seeds are the main colonizers after a disturbance remains unknown. Our goal was to understand whether recolonization by an amphicarpic species after fire was accomplished primarily through germination of seeds produced above-ground or below-ground. We investigated Polygala lewtonii, an amphicarpic, perennial species endemic to fire-prone Florida sandhill and scrub, where fire kills plants but subsequently increases recruitment and population sizes. Polygala lewtonii produces three flower types: above-ground chasmogamous flowers and above-ground and below-ground cleistogamous flowers, with previous research demonstrating chasmogamous flowers produce a much greater proportion of seeds than cleistogamous flowers. We quantified outcrossing in seeds produced by chasmogamous flowers to determine whether it differed from the 100 % self-fertilized below-ground seeds. Approximately 25 % of seeds from chasmogamous flowers showed evidence of cross-pollination. Assuming that chasmogamous flowers produce the majority of the above-ground seeds, as was shown previously, this indicates it is possible to differentiate between germination by above-ground versus below-ground seeds in post-fire colonization. We next compared genetic diversity, admixture, inbreeding and population genetic structure pre- and post-fire. If fire promoted germination of chasmogamous seeds, heterozygosity and admixture would increase, and genetic structure and inbreeding would decrease. Instead, inbreeding and genetic structure increased and admixture decreased, suggesting that the below-ground selfed seeds (with limited dispersal ability) increased their contribution to the population after fire, possibly because fire reduced above-ground seed viability. Additionally, new alleles not found previously in range-wide analyses emerged from the seed bank post-fire. These results suggest that amphicarpy is a powerful adaptation to preserve genetic variation, maintain adaptive potential and promote rapid post-fire colonization.

Prevalencia de sobrepeso y obesidad en escolares jujeños de diferente nivel altitudinal según las referencias IOTF, CDC y OMS / Prevalence of overweight and obesity in students from different altitudinal zones of Jujuy according to three intvernational references (IOTF, CDC and WHO)

Introducción. Se comparan las prevalencias de sobrepeso (SP) y obesidad (OB) en escolares jujeños de distintos niveles altitudinales utilizando las referencias de la International Obesity Task Force (IOTF), de los Centers for Disease Control (CDC) y de la Organización Mundial de la Salud (OMS), y la concordancia entre ellas. Materiales y métodos. Los datos de peso y talla de 15 541 escolares (PROSANE) se agruparon en tierras altas (TA) (= 2500 msnm) y bajas (TB) (< 2500 msnm), y en dos grupos de edad (5 a 6,99 y 11 a 12,99 años). Se calcularon las prevalencias de SP, OB y SP+OB según las referencias. Las diferencias entre variables y prevalencias se establecieron con la prueba de la ?² y la prueba de la t, y la concordancia entre criterios, con el índice kappa. Resultados. Los escolares de las TA presentaron menor peso, talla e índice de masa corporal (IMC) (p< 0,05). Las prevalencias de SP, OB y SP+OB con OMS fueron superiores, excepto para SP en ambos sexos de 11 a 12,99 años de TB y TA. Independientemente de las referencias, el sexo y la edad, las prevalencias de SP, OB y SP+OB fueron, en general, mayores en las TB. La concordancia entre las referencias IOTF/CDC fue buena-muy buena, y entre estas y las de la OMS, regular-moderada. Conclusiones. Los escolares de TA presentaron menor prevalencia de SB y OB. La mejor concordancia se dio entre las referencias IOTF y CDC.

Introduction. Prevalences of overweight and obesity in students from different altitudinal zones of Jujuy are compared using the International Obesity Task Force (IOTF), the Centers for Disease Control (CDC) and the World Health Organization (WHO) references, and the agreement among them. Material and Methods. Weight and height data from 15 541 students were grouped in highlands (HL) (=2500 MASL) and lowlands (LL) (<2500 MASL) and in two age groups (5-6.99 years old and 11-12.99 years old). Overweight and obesity prevalences were calculated according to the different references. The differences in outcome measures and prevalences were established using the ?2 test and the t test, and agreement among the criteria was calculated using the kappa index. Results. Students from the HL had lower weight, height and body mass index (BMI) values (p< 0.05). Overweight and obesity prevalences compared to the WHO reference were higher, except for overweight in students of both sexes, from 11 to 12.99 years old, from the HL and the LL. Regardless of the references, gender and age, overweight and obesity prevalences were generally higher in the LL. Agreement between the IOTF and the CDC was good-very good, and agreement among them and the WHO was fair-moderate. Conclusions. Students from the HL had a lower overweight and obesity prevalence. The greatest agreement was observed between the IOTF and the CDC references.

Prevalencia de sobrepeso y obesidad en escolares jujeños de diferente nivel altitudinal según las referencias IOTF, CDC y OMS / Prevalence of overweight and obesity in students from different altitudinal zones of Jujuy according to three intvernational references (IOTF, CDC and WHO)

Introducción. Se comparan las prevalencias de sobrepeso (SP) y obesidad (OB) en escolares jujeños de distintos niveles altitudinales utilizando las referencias de la International Obesity Task Force (IOTF), de los Centers for Disease Control (CDC) y de la Organización Mundial de la Salud (OMS), y la concordancia entre ellas. Materiales y métodos. Los datos de peso y talla de 15 541 escolares (PROSANE) se agruparon en tierras altas (TA) (= 2500 msnm) y bajas (TB) (< 2500 msnm), y en dos grupos de edad (5 a 6,99 y 11 a 12,99 años). Se calcularon las prevalencias de SP, OB y SP+OB según las referencias. Las diferencias entre variables y prevalencias se establecieron con la prueba de la ?² y la prueba de la t, y la concordancia entre criterios, con el índice kappa. Resultados. Los escolares de las TA presentaron menor peso, talla e índice de masa corporal (IMC) (p< 0,05). Las prevalencias de SP, OB y SP+OB con OMS fueron superiores, excepto para SP en ambos sexos de 11 a 12,99 años de TB y TA. Independientemente de las referencias, el sexo y la edad, las prevalencias de SP, OB y SP+OB fueron, en general, mayores en las TB. La concordancia entre las referencias IOTF/CDC fue buena-muy buena, y entre estas y las de la OMS, regular-moderada. Conclusiones. Los escolares de TA presentaron menor prevalencia de SB y OB. La mejor concordancia se dio entre las referencias IOTF y CDC.(AU)

Introduction. Prevalences of overweight and obesity in students from different altitudinal zones of Jujuy are compared using the International Obesity Task Force (IOTF), the Centers for Disease Control (CDC) and the World Health Organization (WHO) references, and the agreement among them. Material and Methods. Weight and height data from 15 541 students were grouped in highlands (HL) (=2500 MASL) and lowlands (LL) (<2500 MASL) and in two age groups (5-6.99 years old and 11-12.99 years old). Overweight and obesity prevalences were calculated according to the different references. The differences in outcome measures and prevalences were established using the ?2 test and the t test, and agreement among the criteria was calculated using the kappa index. Results. Students from the HL had lower weight, height and body mass index (BMI) values (p< 0.05). Overweight and obesity prevalences compared to the WHO reference were higher, except for overweight in students of both sexes, from 11 to 12.99 years old, from the HL and the LL. Regardless of the references, gender and age, overweight and obesity prevalences were generally higher in the LL. Agreement between the IOTF and the CDC was good-very good, and agreement among them and the WHO was fair-moderate. Conclusions. Students from the HL had a lower overweight and obesity prevalence. The greatest agreement was observed between the IOTF and the CDC references.(AU)

Prevalence of overweight and obesity in students from different altitudinal zones of Jujuy according to three international references (IOTF, CDC and WHO).

INTRODUCTION. Prevalences of overweight and obesity in students from different altitudinal zones of Jujuy are compared using the International Obesity Task Force (IOTF), the Centers for Disease Control (CDC) and the World Health Organization (WHO) references, and the agreement among them. MATERIAL AND METHODS. Weight and height data from 15 541 students were grouped in highlands (HL) (≥2500 MASL) and lowlands (LL) (<2500 MASL) and in two age groups (5-6.99 years old and 11-12.99 years old). Overweight and obesity prevalences were calculated according to the different references. The differences in outcome measures and prevalences were established using the ?2 test and the t test, and agreement among the criteria was calculated using the kappa index. RESULTS. Students from the HL had lower weight, height and body mass index (BMI) values (p< 0.05). Overweight and obesity prevalences compared to the WHO reference were higher, except for overweight in students of both sexes, from 11 to 12.99 years old, from the HL and the LL. Regardless of the references, gender and age, overweight and obesity prevalences were generally higher in the LL. Agreement between the IOTF and the CDC was good-very good, and agreement among them and the WHO was fair-moderate. CONCLUSIONS. Students from the HL had a lower overweight and obesity prevalence. The greatest agreement was observed between the IOTF and the CDC references.

Prevalence of overweight and obesity in students from different altitudinal zones of Jujuy according to three international references (IOTF, CDC and WHO). / Prevalence of overweight and obesity in students from different altitudinal zones of Jujuy according to three international references (IOTF, CDC and WHO).

INTRODUCTION. Prevalences of overweight and obesity in students from different altitudinal zones of Jujuy are compared using the International Obesity Task Force (IOTF), the Centers for Disease Control (CDC) and the World Health Organization (WHO) references, and the agreement among them. MATERIAL AND METHODS. Weight and height data from 15 541 students were grouped in highlands (HL) (2500 MASL) and lowlands (LL) (<2500 MASL) and in two age groups (5-6.99 years old and 11-12.99 years old). Overweight and obesity prevalences were calculated according to the different references. The differences in outcome measures and prevalences were established using the ?2 test and the t test, and agreement among the criteria was calculated using the kappa index. RESULTS. Students from the HL had lower weight, height and body mass index (BMI) values (p< 0.05). Overweight and obesity prevalences compared to the WHO reference were higher, except for overweight in students of both sexes, from 11 to 12.99 years old, from the HL and the LL. Regardless of the references, gender and age, overweight and obesity prevalences were generally higher in the LL. Agreement between the IOTF and the CDC was good-very good, and agreement among them and the WHO was fair-moderate. CONCLUSIONS. Students from the HL had a lower overweight and obesity prevalence. The greatest agreement was observed between the IOTF and the CDC references.