APHM, Timone Enfant, Service de pédiatrie multidisciplinaire, Marseille, France.
Aix Marseille Univ, INSERM, MMG, Marseille, France.
Bioessays. 2023 Jul;45(7):e2200243. doi: 10.1002/bies.202200243. Epub 2023 Apr 19.
Lactase persistence/persistent (LP), the ability to express the lactase enzyme in adults, is one of the most strongly selected phenotypes in humans. It is encoded by at least five genetic variants that have rapidly become widespread in various human populations. The underlying selective mechanism is not clear however, because dairy products in general are well tolerated in adults, even by lactase non-persistence/persistent (LNP) individuals. Cultural adaptations to milk consumption, notably fermentation and transformation, which can provide most of the energy (protein, fat) to both LP and LNP individuals without any associated cost seem to have been common in ancient societies. Here, we propose that selection for LP occurred through increased glucose/galactose (energy) from fresh milk intake in early childhood, a crucial period for growth. At the age of weaning indeed, lactase activity has already begun to decline in LNP individuals so the gain in energy from fresh milk by LP children represents a major fitness increase.
乳糖持续存在/持久（LP），即成年人表达乳糖酶的能力，是人类中选择最强的表型之一。它由至少五种遗传变异体编码，这些变异体在各种人类群体中迅速广泛传播。然而，潜在的选择机制尚不清楚，因为乳制品在成年人中通常是可以耐受的，即使是非乳糖持续存在/持久（LNP）个体也是如此。对牛奶消费的文化适应，特别是发酵和转化，可以为 LP 和 LNP 个体提供大部分能量（蛋白质、脂肪），而不会带来任何相关成本，这在古代社会似乎很常见。在这里，我们提出 LP 的选择是通过从幼年时摄入新鲜牛奶中获得更多的葡萄糖/半乳糖（能量）而发生的，这是生长的关键时期。事实上，在断奶年龄，LNP 个体的乳糖酶活性已经开始下降，因此 LP 儿童从新鲜牛奶中获得的能量增加代表了一个主要的适应度增加。
