Despite the increasing demand for diverse Centella asiatica (L.) Urb. species in Korea, studies on related topics are limited, with the majority of studies focusing on functional evaluations, rather than genetic diversity. Therefore, in this study, we explored the genetic diversity of C. asiatica, a valuable medicinal plant collected from six island regions in Korea, using genotyping-by-sequencing analysis. Specifically, we aimed to understand plant genetic variations, population structure and the potential for conservation and genetic improvement. The results indicated relatively high genetic diversity among the samples collected from the six island regions but low genetic differentiation among their populations. Two distinct genetic clusters were identified; however, even within these clusters, genetic differentiation was minimal. The lack of significant isolation-by-distance patterns and evidence of potential clonal spread suggested that some individuals that adapted to colder Korean conditions achieved dominance. This study highlights the importance of assessing the genetic diversity of native C. asiatica in Korea and explores the possibility of conducting follow-up studies to understand the phytochemical content and bioactivity variations among the individuals. This information can aid in the selection of superior resources and effective utilization of plant genetic resources for cultivar development and other applications.

In a longitudinal study including 642 healthy 8–11-year-old Danish children, we investigated associations between vitamin D dependent SNP and serum 25-hydroxyvitamin D (25(OH)D) concentrations across a school year (August–June). Serum 25(OH)D was measured three times for every child, which approximated measurements in three seasons (autumn, winter, spring). Dietary and supplement intake, physical activity, BMI and parathyroid hormone were likewise measured at each time point. In all, eleven SNP in four vitamin D-related genes: Cytochrome P450 subfamily IIR1 (CYP2R1); 7-dehydrocholesterol reductase/nicotinamide adenine dinucleotide synthetase-1(DHCR7/NADSYN1); group-specific complement (GC); and vitamin D receptor were genotyped. We found minor alleles of CYP2R1 rs10500804, and of GC rs4588 and rs7041 to be associated with lower serum 25(OH)D concentrations across the three seasons (all P<0·01), with estimated 25(OH)D differences of −5·8 to −10·6 nmol/l from major to minor alleles homozygosity. In contrast, minor alleles homozygosity of rs10741657 and rs1562902 in CYP2R1 was associated with higher serum 25(OH)D concentrations compared with major alleles homozygosity (all P<0·001). Interestingly, the association between season and serum 25(OH)D concentrations was modified by GC rs7041 (Pinteraction=0·044), observed as absence of increase in serum 25(OH)D from winter to spring among children with minor alleles homozygous genotypes compared with the two other genotypes of rs7041 (P<0·001). Our results suggest that common genetic variants are associated with lower serum 25(OH)D concentrations across a school year. Potentially due to modified serum 25(OH)D response to UVB sunlight exposure. Further confirmation and paediatric studies investigating vitamin D-related health outcomes of these genotypic differences are needed.

The relationship between intake of dietary fibre and risk of colon cancer has been studied for 30 years and still the data are inconclusive. There are many possible reasons for this outcome, and they include a failure to consider exposure to dietary fibre separately by source, or colon cancers separately by subsite. These potential confounders have been known for at least 20 years. However, the disease is normally considered by epidemiologists as a single entity. More recently, it has become clear that colon cancer can arise via various histological pathways, and by various genetic pathways. There is no reason at all for assuming that risk factors for these possible pathways are the same. There is a need, therefore, for a more detailed approach to the study of diet and colon cancer, with fibre source and cancer subsite, genetic pathway and histological pathway taken into account.