Lactase haplotype frequencies in Caucasians: association with the lactase persistence/non‐persistence polymorphism

@article{Harvey1998LactaseHF,
  title={Lactase haplotype frequencies in Caucasians: association with the lactase persistence/non‐persistence polymorphism},
  author={C. B. Harvey and Edward J. Hollox and Mark Poulter and Yangxi Wang and Mauro Rossi and Salvatore Auricchio and Tariq H Iqbal and Brian T Cooper and Rachel Barton and Martin Sarner and Riitta Korpela and Dallas M. Swallow},
  journal={Annals of Human Genetics},
  year={1998},
  volume={62}
}
A genetic polymorphism is responsible for determining that some humans express lactase at high levels throughout their lives and are thus lactose tolerant, while others lose lactase expression during childhood and are lactose intolerant. We have previously shown that this polymorphism is controlled by an element or elements which act in cis to the lactase gene. We have also reported that 7 polymorphisms in the lactase gene are highly associated and lead to only 3 common haplotypes (A, B and C… Expand
Lactase haplotype diversity in the Old World.
TLDR
It is suggested that genetic drift was important in shaping the general pattern of non-African haplotype diversity, with recent directional selection in northern Europeans for the haplotype associated with lactase persistence. Expand
A novel polymorphism associated with lactose tolerance in Africa: multiple causes for lactase persistence?
TLDR
A cohort study of lactose digester and non-digester Sudanese volunteers shows there is no association of -13910*T or the A haplotype with lactase persistence, and reveals the complexity of this phenotypic polymorphism and highlights the limitations of C-13910T as a diagnostic test for lact enzyme persistence status, at least for people with non-European ancestry. Expand
Multiple Rare Variants as a Cause of a Common Phenotype: Several Different Lactase Persistence Associated Alleles in a Single Ethnic Group
TLDR
A cohort of 107 milk-drinking Somali camel-herders from Ethiopia is examined, showing that increased diversity can accompany selection, and contrasts with the well-documented observation that positive selection decreases diversity by driving up the frequency of a single advantageous allele. Expand
Evolutionary and molecular genetics of regulatory alleles responsible for lactase persistence
TLDR
The results show that different mechanisms lead to a disruption of the normal down-regulation of lactase in adult life, and the finding of an extended region of high linkage disequilibrium in all populations, and an extended B haplotype is discussed in relation to the methods to study selection. Expand
Genetics of Lactase Persistence and Lactose Intolerance
TLDR
A putative causal nucleotide change has been identified and occurs on the background of a very extended haplotype that is frequent in Northern Europeans, where lactase persistence is frequent and does not explain all the variation in lactase expression. Expand
Genetics of lactase persistence and lactose intolerance.
  • D. Swallow
  • Biology, Medicine
  • Annual review of genetics
  • 2003
TLDR
A putative causal nucleotide change has been identified and occurs on the background of a very extended haplotype that is frequent in Northern Europeans, where lactase persistence is frequent. Expand
Lactose digestion and the evolutionary genetics of lactase persistence
TLDR
Access is provided to a database of worldwide distributions of lactase persistence and of the C-13910*T allele, as well as reviewing lactase molecular and population genetics and the role of selection in determining present day distributions of the lactases persistence phenotype. Expand
Diversity of lactase persistence alleles in Ethiopia: signature of a soft selective sweep.
TLDR
The LCT enhancer sequence is examined in a large lactose-tolerance-tested Ethiopian cohort of more than 350 individuals and it is shown that a further SNP, -14009T>G (ss 820486563), is significantly associated with lactOSE-digester status, and in vitro functional tests confirm that the - 14009(∗)G allele also increases expression of an LCT promoter construct. Expand
Stability or variation? Patterns of lactase gene and its enhancer region distributions in Brazilian Amerindians.
TLDR
The LCT was highly polymorphic in the present sample showing 15 haplotypes with a heterogeneous distribution among the four Amerindian populations, and it is suggested that the presence of the LP allele could have been determined by a de novo mutation. Expand
Evidence of still-ongoing convergence evolution of the lactase persistence T-13910 alleles in humans.
TLDR
The data about global allelic haplotypes of the lactose-tolerance variant imply that the T(-13910) allele has been independently introduced more than once and that there is a still-ongoing process of convergent evolution of the LP alleles in humans. Expand
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TLDR
This work exploited known DNA 'marker' polymorphisms within the exons of the lactase gene to examine the expression of the individual lactase mRNA transcripts from persistent and non-persistent individuals in order to determine whether the regulation is in cis or trans. Expand
DNA Polymorphisms in the Lactase Gene
TLDR
Simple polymerase chain reaction-based procedures were used, combined with silver staining as a method of detection, and a region of linkage disequilibrium was observed which spans the whole coding region of the lactase gene (∼ 60–70 kb). Expand
The genetically programmed down-regulation of lactase in children.
TLDR
Analysis of 866 children showed evidence that the lactase persistence/nonpersistence polymorphism began before 5 years of age, although the onset and extent are somewhat variable. Expand
Lactase polymorphism in adult British natives: estimating allele frequencies by enzyme assays in autopsy samples.
TLDR
Circumstantial evidence and statistical analyses suggest that the trimodal distribution is due to the different levels of lactase activity in the three genotypes--homozygous persistent, heterozygous, and homozygous nonpersistent, and that it is possible to correct for "nongenetic" variation by using sucrase as an internal standard. Expand
Structure of the chromosomal gene and cDNAs coding for lactase-phlorizin hydrolase in humans with adult-type hypolactasia or persistence of lactase.
TLDR
It is concluded that humans with high or low levels of lactase can code for identical LPH enzymes. Expand
Studies on the expression of intestinal lactase in different individuals.
TLDR
The results suggest that the lactase persistence polymorphism is controlled at the levels of enzyme activity, protein, and messenger RNA, though there may be some heterogeneity of the lactases non-persistence phenotype. Expand
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The HLA loci and electrophoretic loci presented here yield sets of genetic distances that are highly correlated and that both correspond closely to the actual geographic distances among the European populations. Expand
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TLDR
This analysis supports the hypothesis that high adult lactose digestion capacity is an adaptation to dairying but does not support the hypotheses that lactose ingestion capacity is additionally selected for either at high latitudes or in highly arid environments. Expand
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TLDR
The mosaicism observed in the 12 Hypolactasic individuals suggests that the differentiation of the columnar cells along the villus is not homogeneous, and the existence of two phenotypes of adult-type hypolactasia in the population studied is suggested. Expand
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TLDR
The development of the intricate mechanisms of lactase synthesis in the mammary gland and of lactose digestion in the intestinal tract would run counter to evolutionary economy if lactose did not convey a special selective advantage during the suckling period. Expand
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