Evolution of lactase persistence: an example of human niche construction

Abstract

Niche construction is the process by which organisms construct important components of their local environment in ways that introduce novel selection pressures. Lactase persistence is one of the clearest examples of niche construction in humans. Lactase is the enzyme responsible for the digestion of the milk sugar lactose and its production decreases after the weaning phase in most mammals, including most humans. Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (213910*T ) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle East. Current estimates for the age of lactase persistence-associated alleles bracket those for the origins of animal domestication and the culturally transmitted practice of dairying. We report new data on the distribution of 213910*T and summarize genetic studies on the diversity of lactase persistence worldwide. We review relevant archaeological data and describe three simulation studies that have shed light on the evolution of this trait in Europe. These studies illustrate how genetic and archaeological information can be integrated to bring new insights to the origins and spread of lactase persistence. Finally, we discuss possible improvements to these models.

Human niche construction in interdisciplinary focus

“…Gerbault et al [51] in this issue review the current understanding of perhaps the most well-cited case of gene -culture coevolution, that of lactase persistence and dairy farming. Their paper takes an interdisciplinary approach, considering new genetic data, archaeological evidence and simulation modelling to explore how this coevolutionary process took place.…”

Kohlenhydratmalassimilation bei der Hashimoto-Thyreoiditis

“…Mit der Kohlenhydratmalassimilation wurden in der Literatur bereits, neben der klassischen gastrointestinalen Symptomatik, diverse pathologische Folge-und Mangelzustände in Verbindung gebracht (29)(30)(31)(32)(33)(34)(35) Die Laktase ermöglicht somit die Digestion und die Nutzung der Laktose, ist jedoch nur bei der Geburt und Stillzeit reichlich bei allen Menschen und Säugetieren vorhanden (27,40).…”

“…Die Laktase-Persistenz enspricht der genetisch über Single-Nucleotide-Polymorphismen vermittelten erhaltenen Expression des Enzyms Laktase (21,27,97). Die SingleNucleotide-Polymorphismen sind vor tausenden Jahren infolge von Mutationen entstanden (97).…”

Adaptation and niche construction in human prehistory: a case study from the southern Scandinavian Late Glacial

“…In fact, the process involved not simply the inheritance of a tradition but also the transmission of a new niche, because the actual descendants of the cereal crops and animals that had originally been domesticated were being carried along as part of the dispersal'. The evolutionary success of farmers under this model is largely due to the powerful positive NC that is part and parcel of most agricultural societies [55]. Equally, however, environmental archaeological data also indicate the collapse of such early agricultural societies in some regions because farming practices destroyed the environment [80].…”

“…Gene frequency patterns in both modern and ancient DNA can, for instance, be used to demonstrate the evident success of early farmers and their NC behaviours involving a range of domesticated animals and plants (e.g. [54][55][56]). However, genetic change is merely the endpoint of what is best thought of as a continuum of processes [57 -59].…”