Hunting for the LCT-13910*T Allele between the Middle Neolithic and the Middle Ages Suggests Its Absence in Dairying LBK People Entering the Kuyavia Region in the 8th Millennium BP

Abstract

Populations from two medieval sites in Central Poland, Stary Brześć Kujawski-4 (SBK-4) and Gruczno, represented high level of lactase persistence (LP) as followed by the LCT-13910*T allele’s presence (0.86 and 0.82, respectively). It was twice as high as in contemporaneous Cedynia (0.4) and Śródka (0.43), both located outside the region, higher than in modern inhabitants of Poland (0.51) and almost as high as in modern Swedish population (0.9). In an attempt to explain the observed differences its frequency changes in time were followed between the Middle Neolithic and the Late Middle Ages in successive dairying populations on a relatively small area (radius ∼60km) containing the two sites. The introduction of the T allele to Kuyavia 7.4 Ka BP by dairying LBK people is not likely, as suggested by the obtained data. It has not been found in any of Neolithic samples dated between 6.3 and 4.5 Ka BP. The identified frequency profile indicates that both the introduction and the beginning of selection could have taken place approx. 4 millennia after first LBK people arrived in the region, shifting the value of LP frequency from 0 to more than 0.8 during less than 130 generations. We hypothesize that the selection process of the T allele was rather rapid, starting just after its introduction into already milking populations and operated via high rates of fertility and mortality on children after weaning through life-threatening conditions, favoring lactose-tolerant individuals. Facing the lack of the T allele in people living on two great European Neolithization routes, the Danubian and Mediterranean ones, and based on its high frequency in northern Iberia, its presence in Scandinavia and estimated occurrence in Central Poland, we propose an alternative Northern Route of its spreading as very likely. None of the successfully identified nuclear alleles turned out to be deltaF508 CFTR.

Analysis of LCT-13910 genotypes and bone mineral density in ancient skeletal materials

“…It was reported that LCT-13910 CT and TT genotypes associated with LT were subjected in Europe to a strong positive selection for over 3000 years. The TT and CT genotypes were absent in early Neolithic Farmer populations and present in only 10% of Bronze Age European people [ 9 , 10 , 11 ]. In Europe the LT has increased from Iron Age through Medieval Period till present day times [ 12 ].…”

New insights into Neolithic milk consumption through proteomic analysis of dental calculus

“…It is important to note, however, that due to recent discoveries of LP prevalence in the European Neolithic (Burger et al 2007;Gamba et al 2014;Witas et al 2015;Olalde et al 2018;Brace et al 2019), it is unlikely that the British Neolithic individuals studied here would have carried the genetic mutation associated with lactase persistence. Human remains from neither Hambledon Hill nor Hazleton North have been subjected to ancient DNA analysis to date, but none of the individuals (n = 3) genetically analysed thus far from Banbury Lane have a derived lactase persistence allele (Brace et al 2019).…”

“…Advances in next-generation sequencing technologies and the emergence of full genome characterisation of archaeological samples however now suggest that LP may not have been prevalent in the Neolithic, but instead present only in very low frequencies across the population, if present at all. The absence of LP in European Neolithic populations has now been noted in a number of studies (e.g., Burger et al 2007;Gamba et al 2014;Witas et al 2015;Olalde et al 2018;Brace et al 2019), and Allentoft et al (2015) suggest that LP had a very low frequency (5-10%) even in Bronze Age European populations, indicating that LP is the result of more recent positive selection. Similarly, a large-scale study by Mathieson et al (2015) suggests that LP in Europe only became under strong selection within the last 4000 years.…”

Population genomics on the origin of lactase persistence in Europe and South Asia

“…A recent study of 400 Neolithic, Chalcolithic and Bronze Age Europeans (Olalde et al, 2018) observed that the T allele remained at a very low frequency across the transition from the Neolithic period to the Bell Beaker and Bronze Age periods, both in Britain and continental Europe, with a major increase in its frequency occurring only within the last 3500 years (Brace et al, 2018). Table 1 summarizes some such results of Allentoft et al (2015), Mathieson et al (2015), and Olalde et al (2018) based on the Central European chronology in Haak et al (2015); readers may also refer to Witas et al (2015), Liebert et al (2017) and Ségurel and Bon (2017).…”