Institut de Biologia Evolutiva, CSIC-UPF, Dr. Aiguader 88, 08003 Barcelona, Spain.
Biol Lett. 2009 Dec 23;5(6):809-11. doi: 10.1098/rsbl.2009.0532. Epub 2009 Aug 12.
The bitter taste perception (associated with the ability or inability to taste phenylthiocarbamide) is mediated by the TAS2R38 gene. Most of the variation in this gene is explained by three common amino-acid polymorphisms at positions 49 (encoding proline or alanine), 262 (alanine or valine) and 296 (valine or isoleucine) that determine two common isoforms: proline-alanine-valine (PAV) and alanine-valine-isoleucine (AVI). PAV is the major taster haplotype (heterozygote and homozygote) and AVI is the major non-taster haplotype (homozygote). Amino acid 49 has the major effect on the distinction between tasters and non-tasters of all three variants. The sense of bitter taste protects us from ingesting toxic substances, present in some vegetables, that can affect the thyroid when ingested in large quantities. Balancing selection has been used to explain the current high non-taster frequency, by maintaining divergent TAS2R38 alleles in humans. We have amplified and sequenced the TAS2R38 amino acid 49 in the virtually uncontaminated Neanderthal sample of El Sidrón 1253 and have determined that it was heterozygous. Thus, this Neanderthal was a taster individual, although probably slightly less than a PAV homozygote. This indicates that variation in bitter taste perception pre-dates the divergence of the lineages leading to Neanderthals and modern humans.
苦味感知（与能否品尝苯硫脲有关）由 TAS2R38 基因介导。该基因的大部分变异可归因于位置 49（编码脯氨酸或丙氨酸）、262（丙氨酸或缬氨酸）和 296（缬氨酸或异亮氨酸）的三个常见氨基酸多态性，这些多态性决定了两种常见的同工型：脯氨酸-丙氨酸-缬氨酸（PAV）和丙氨酸-缬氨酸-异亮氨酸（AVI）。PAV 是主要的味觉体基因型（杂合子和纯合子），而 AVI 是主要的非味觉体基因型（纯合子）。在所有三种变体中，氨基酸 49 对区分味觉者和非味觉者的影响最大。苦味感知有助于我们避免摄入某些蔬菜中的有毒物质，这些物质如果大量摄入会影响甲状腺。平衡选择被用来解释当前高非味觉体频率，通过在人类中维持分化的 TAS2R38 等位基因。我们已经扩增和测序了 El Sidrón 1253 中几乎未受污染的尼安德特人样本中的 TAS2R38 氨基酸 49，并确定其为杂合子。因此，这个尼安德特人是一个味觉者个体，尽管可能略逊于 PAV 纯合子。这表明苦味感知的变异发生在尼安德特人和现代人类的谱系分化之前。
