The Sahel/Savannah belt harbors diverse populations with different demographic histories and different subsistence patterns. However, populations from this large African region are notably under-represented in genomic research. To investigate the population structure and adaptation history of populations from the Sahel/Savannah space, we generated dense genome-wide genotype data of 327 individuals-comprising 14 ethnolinguistic groups, including 10 previously unsampled populations. Our results highlight fine-scale population structure and complex patterns of admixture, particularly in Fulani groups and Arabic-speaking populations. Among all studied Sahelian populations, only the Rashaayda Arabic-speaking population from eastern Sudan shows a lack of gene flow from African groups, which is consistent with the short history of this population in the African continent. They are recent migrants from Saudi Arabia with evidence of strong genetic isolation during the last few generations and a strong demographic bottleneck. This population also presents a strong selection signal in a genomic region around the CNR1 gene associated with substance dependence and chronic stress. In Western Sahelian populations, signatures of selection were detected in several other genetic regions, including pathways associated with lactase persistence, immune response, and malaria resistance. Taken together, these findings refine our current knowledge of genetic diversity, population structure, migration, admixture and adaptation of human populations in the Sahel/Savannah belt and contribute to our understanding of human history and health.
- MeSH
- dechové testy metody MeSH
- diferenciální diagnóza MeSH
- laktasa nedostatek MeSH
- lidé MeSH
- malabsorpční syndromy diagnóza etiologie klasifikace terapie MeSH
- nesnášenlivost laktózy * diagnóza dietoterapie etiologie patofyziologie terapie MeSH
- probiotika terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
OBJECTIVES: Archeological evidence shows that first nomadic pastoralists came to the African Sahel from northeastern Sahara, where milking is reported by ~7.5 ka. A second wave of pastoralists arrived with the expansion of Arabic tribes in 7th-14th century CE. All Sahelian pastoralists depend on milk production but genetic diversity underlying their lactase persistence (LP) is poorly understood. MATERIALS AND METHODS: We investigated SNP variants associated with LP in 1,241 individuals from 29 mostly pastoralist populations in the Sahel. Then, we analyzed six SNPs in the neighboring fragment (419 kb) in the Fulani and Tuareg with the -13910*T mutation, reconstructed haplotypes, and calculated expansion age and growth rate of this variant. RESULTS: Our results reveal a geographic localization of two different LP variants in the Sahel: -13910*T west of Lake Chad (Fulani and Tuareg pastoralists) and -13915*G east of there (mostly Arabic-speaking pastoralists). We show that -13910*T has a more diversified haplotype background among the Fulani than among the Tuareg and that the age estimate for expansion of this variant among the Fulani (~8.5 ka) corresponds to introduction of cattle to the area. CONCLUSIONS: This is the first study showing that the "Eurasian" LP allele -13910*T is widespread both in northern Europe and in the Sahel; however, it is limited to pastoralists in the Sahel. Since the Fulani haplotype with -13910*T is shared with contemporary Eurasians, its origin could be in a region encompassing the Near East and northeastern Africa in a population ancestral to both Saharan pastoralists and European farmers.
- MeSH
- antropologie fyzická MeSH
- Arabové genetika statistika a číselné údaje MeSH
- běloši genetika statistika a číselné údaje MeSH
- černoši * genetika statistika a číselné údaje MeSH
- dieta MeSH
- etnicita * genetika statistika a číselné údaje MeSH
- haplotypy MeSH
- jednonukleotidový polymorfismus genetika MeSH
- laktasa genetika MeSH
- lidé MeSH
- mléko MeSH
- osoby s přechodným pobytem a migranti MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- severní Afrika MeSH
BACKGROUND: Human population history in the Holocene was profoundly impacted by changes in lifestyle following the invention and adoption of food-production practices. These changes triggered significant increases in population sizes and expansions over large distances. Here we investigate the population history of the Fulani, a pastoral population extending throughout the African Sahel/Savannah belt. RESULTS: Based on genome-wide analyses we propose that ancestors of the Fulani population experienced admixture between a West African group and a group carrying both European and North African ancestries. This admixture was likely coupled with newly adopted herding practices, as it resulted in signatures of genetic adaptation in contemporary Fulani genomes, including the control element of the LCT gene enabling carriers to digest lactose throughout their lives. The lactase persistence (LP) trait in the Fulani is conferred by the presence of the allele T-13910, which is also present at high frequencies in Europe. We establish that the T-13910 LP allele in Fulani individuals analysed in this study lies on a European haplotype background thus excluding parallel convergent evolution. We furthermore directly link the T-13910 haplotype with the Lactase Persistence phenotype through a Genome Wide Association study (GWAS) and identify another genomic region in the vicinity of the SPRY2 gene associated with glycaemic measurements after lactose intake. CONCLUSIONS: Our findings suggest that Eurasian admixture and the European LP allele was introduced into the Fulani through contact with a North African population/s. We furthermore confirm the link between the lactose digestion phenotype in the Fulani to the MCM6/LCT locus by reporting the first GWAS of the lactase persistence trait. We also explored other signals of recent adaptation in the Fulani and identified additional candidates for selection to adapt to herding life-styles.
INTRODUCTION: To reduce the risk of insulin resistance in obesity in children with lactase gene genotypes, we studied the factors that stimulate the chronic inflammatory process. MATERIAL AND METHODS: 109 children 6-18 years of age were investigated. The main group (n = 56) was presented by children with signs of insulin-resistant obesity according to the criteria of the European Society of Endocrinology and the Pediatric Endocrine Society. The control group (n = 53) included obese children without insulin resistance. A comprehensive clinical examination, food diary analysis, genotyping of the lactase gene by means of the polymerase chain reaction, the Immunochemical Test Method with Electrochemiluminescent Detection of basal insulinemia, Hydrogen breath test with lactose load, sequential analysis, ROC analysis were carried out. RESULTS: Clinical manifestations of lactose maldigestion in a child increased the risk of possible insulin resistance (prognostic coefficient (PC +2.6), as well as the presence of the lactase C/C 13910 gene genotype (PC +5.8) did. The genotype C/T 13910 in children had a protective effect on the risk of obesity (PC -2.9). The lowest risk of insulin-resistant obesity in observed among children with the genotype T/T 13910 (PC -12). CONCLUSION: The presence of the C/C 13910 genotype of the lactase gene is the main factor formation of insulin resistance in children's obesity. What is known? The genotype C/C 13910 of the lactase gene as a risk factor for the chronic inflammatory process in the body. What is New? Genotype C/C 13910 of the lactase gene as a risk factor for insulin-resistant obesity in children.
- MeSH
- dítě MeSH
- fenotyp MeSH
- genetická predispozice k nemoci * MeSH
- genetické markery MeSH
- genotyp * MeSH
- inzulinová rezistence genetika MeSH
- jednonukleotidový polymorfismus * MeSH
- laktasa genetika MeSH
- lidé MeSH
- logistické modely MeSH
- mladiství MeSH
- obezita dětí a dospívajících genetika MeSH
- rizikové faktory MeSH
- ROC křivka MeSH
- studie případů a kontrol MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Schopnost trávit laktózu je zásadní v kojeneckém věku, kdy je mléko dominantní složkou stravy. U novorozence je aktivita laktázy závislá na gestačním stáří a vzácně je ovlivněna vrozeným deficitem laktázy. Fyziologicky klesá aktivita střevní laktázy v důsledku přirozeného vývoje (laktázová non‑perzistence) nebo v důsledku onemocnění střeva (celiakie, Crohnova nemoc atd). Laktózová intolerance způsobuje kromě průjmu, bolestí břicha a meteorismu i další systémové příznaky. Léčba spočívá v dietě s omezením příjmu laktózy.
The ability to digest lactose is an important condition in infant´s life, while being fed by breastmilk or formula. In new-born thisintestinal function depends on gestational age or can be rarely affected by inborn lactase deficiency. Lactase activity may decreaseduring following periods by physiologic development (lactase non-persistence) or by gastrointestinal diseases (celiac disease,Crohn´s). Lactose intolerance causes often diarrhoea, abdominal pain, meteorism, sometimes can be accompanied by complexsymptoms. The treatment of lactose intolerance concerns of low lactose diet.
- Klíčová slova
- LCT gen,
- MeSH
- alergie na mléko * MeSH
- diagnostické techniky a postupy přístrojové vybavení MeSH
- dospělí MeSH
- kojenec MeSH
- laktasa MeSH
- laktosa MeSH
- lidé MeSH
- nemoci střev komplikace MeSH
- nesnášenlivost laktózy * diagnóza dietoterapie etiologie klasifikace terapie MeSH
- novorozenec MeSH
- střevní mikroflóra MeSH
- Check Tag
- dospělí MeSH
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- přehledy MeSH
The paper presents the results of a study of the Benedict test for deciding the diagnosis of lactose intolerance in children and the effectiveness of lactase drugs. Benedict test is one of the standard methods for the diagnosis of lactose intolerance in children. Drugs with lactase enzyme that helps break down lactose (hydrolysis) into two simple sugars, glucose and galactose, which simplifies digestion. Lactase drugs has been shown to be the best way to preserve natural feeding in children with lactose intolerance, since the lactase composition is involved in the breakdown and absorption of carbohydrates and proteins, produce essential vitamins for improving the health and immunity of the child, normalize the composition of the intestinal flora.
- MeSH
- feces chemie MeSH
- kojenec MeSH
- laktasa chemie nedostatek MeSH
- laktózový toleranční test * metody statistika a číselné údaje MeSH
- lidé MeSH
- nesnášenlivost laktózy * diagnóza dietoterapie MeSH
- novorozenec MeSH
- průjem kojenců etiologie MeSH
- průjem dietoterapie etiologie MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- validační studie MeSH
- MeSH
- alergie na mléko diagnóza MeSH
- laktasa nedostatek MeSH
- lidé MeSH
- mléko * MeSH
- nesnášenlivost laktózy MeSH
- Check Tag
- lidé MeSH
