摘要：左撇子现象在家族中普遍存在，部分是遗传因素。左撇子遗传模型的早期假设是只有一个基因发挥作用。左撇子倾向阈值多基因模型是一种新的左撇子遗传模型。新模型解决了旧模型的关键问题。

The Liability-Threshold Polygenic Model of Left-Handedness

左撇子倾向的阈值多基因模型

A new model tries to explain the genetics of left-handedness.

一种新模型试图解释左撇子的遗传学。

Posted September 14, 2025 | Reviewed by Lybi Ma

发布于 2025 年 9 月 14 日 | Lybi Ma 审阅

Left-handedness runs in families and is partly genetic.Older genetic models of left-handedness assumed that only one gene plays a roles.The liability-threshold polygenic model of left-handedness is a new model of left-handedness genetic.

左撇子现象在家族中普遍存在，部分是遗传因素。左撇子遗传模型的早期假设是只有一个基因发挥作用。左撇子倾向阈值多基因模型是一种新的左撇子遗传模型。新模型解决了旧模型的关键问题。

The new model solves the key problem of older models.Genes play a role in left-handedness

基因在左撇子中起着重要作用

Have you ever wondered why some people are left-handed while most people are right-handed?

您是否想过什么有些人是左撇子，而大多数人是右撇子？

The science behind this simple difference is more complicated than you might think!

这个简单差异背后的科学原理比你想象的要复杂得多！

About 10.6 percent of people are left-handed (Papadatou-Pastou and co-workers, 2020). It has been known for a long time that left-handedness runs in families. Two left-handed parents have a higher chance of having a left-handed child than two right-handed parents. Therefore, genes likely play a role in determining whether someone is born left-handed or right-handed. For a long time, scientists believed that there was just one handedness gene, but recent research has proven that this idea is wrong. Instead, we now know that more than 40 genes play a role in determining whether someone is left-handed or right-handed (Cuellar-Partida and co-workers, 2021).

大约 10.6% 的人是左撇子（Papadatou-Pastou 及其同事，2020 年）。人们早就知道左撇子会在家族中遗传。如果父母双方都是左撇子，生出左撇子的几率比父母双方都是右撇子要高。因此，基因很可能在决定一个人是天生左撇子还是右撇子方面发挥了作用。长期以来，科学家们认为只有一种惯用手基因，但最近的研究证明这种想法是错误的。相反，我们现在知道，有 40 多个基因在决定一个人是左撇子还是右撇子方面发挥作用（Cuellar-Partida 及其同事，2021 年）。

A new model of left-handedness genetics

左撇子遗传学的新模型

A major problem in research on the genetics of left-handedness is that many of the old theoretical models that used to explain left-handedness no longer fit the research data from modern genetic studies, mostly because they assumed that only one gene plays a role in left-handedness. In contrast, a genetic model of left-handedness needs to consider that it is polygenic; many genes play a role (Ocklenburg and co-workers, 2025). This is, by the way, the case for pretty much every psychological variable that is investigated in genetic psychology; only very few things are determined by single genes!

左撇子遗传学研究的一个主要问题是，许多过去用于解释左撇子的理论模型不再适用于现代遗传学的研究数据，主要是因为它们假设只有一个基因在左撇子中起作用。相反，左撇子的遗传模型需要考虑它是多基因的；许多基因都在发挥作用（ Ocklenburg 及其同事，2025）。顺便说一句，遗传心理学研究的几乎所有心理变量都是如此；只有极少数因素是由单个基因决定的！

An important recent development in left-handedness research is the publication of the liability-threshold polygenic model of left-handedness by scientist Silvia Paracchini, a genetics researcher from the School of Medicine at the University of St Andrews in Scotland (Paracchini, 2024; Ocklenburg and co-workers, 2025, for an overview).

左撇子研究领域最近的一项重要进展是苏格兰圣安德鲁斯大学医学院遗传学研究员 Silvia Paracchini 发表了左撇子倾向阈值多基因模型（Paracchini，2024 年；Ocklenburg 及其同事，2025 年，概述）。

As pointed out above, more than 40 genes play a role in left-handedness. Functionally, these genes mostly play a role in the early development of various aspects of the brain, such as the growth and guidance of axons (projections of nerve cells that transport neural information) or the cytoskeleton of brain cells. For each of these genes, a person can have different variants, that is, a version of the gene that shows minimal differences from the same gene in other people. For each gene, there is a specific variant that makes left-handedness more likely and other variants that make right-handedness more likely. The liability-threshold polygenic model of left-handedness now assumes that it is not one specific gene that determines handedness. Instead, it assumes that someone becomes left-handed if they accumulate many of the variants that favor left-handedness. If a person has enough of these left-handedness variants in their genome, they pass a developmental threshold that puts their brain on a developmental trajectory towards left-handedness. If a person has only a few or none of the left-handedness variants, they become right-handed. Therefore, it does not matter at all which specific left-handedness variants somebody has, but how many. This also implies that two left-handers can have completely different gene variants causing their left-handedness, which obviously makes research on the genetics of left-handedness very complicated!

如上所述，超过40个基因与左撇子习性相关。从功能上讲，这些基因主要在大脑各个方面的早期发育中发挥作用，例如轴突（传递神经信息的神经细胞突起）的生长和引导，以及脑细胞的细胞骨架。对于这些基因，每个人可能拥有不同的变异，也就是说，该基因的某个版本与其他人的相同基因差异极小。每个基因都有一个特定的变异使左撇子习性更有可能，而其他变异则使右撇子习性更有可能。左撇子习性的责任阈值多基因模型现在假设，决定惯用手性的并非某个特定的基因。相反，它假设，如果一个人积累了许多有利于左撇子的变异，他就会变成左撇子。如果一个人的基因组中存在足够多的左撇子变异，他们就会跨过一个发育阈值，从而使他们的大脑走上向左撇子发展的轨迹。如果一个人只有少数左撇子变异，或者根本没有左撇子变异，他们就会变成右撇子。因此，一个人具体有哪些左撇子变异并不重要，重要的是有多少个变异。这也意味着两个左撇子可能拥有完全不同的导致他们成为左撇子的基因变异，这显然使得左撇子遗传学的研究变得非常复杂！

Takeaway: A major step towards understanding the genetics of left-handedness

要点：向理解左撇子遗传学迈出重要一步

The liability-threshold polygenic model of left-handedness by Paracchini solves a major problem of older models of handedness genetics by integrating the findings that handedness is determined by many genes! Now, handedness researchers need to put it to the test in experimental studies.

帕拉基尼提出的左撇子倾向阈值多基因模型，整合了惯用手由多个基因决定的发现，解决了旧惯用手遗传学模型的一个主要问题！现在，惯用手研究人员需要通过实验研究来检验它。

来源：左右图史