Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Radcliffe Observatory Quarter, Oxford, United Kingdom; Oxford Centre for Collaborative Applied Mathematics, Mathematical Institute, University of Oxford, Oxford, United Kingdom.
Dev Dyn. 2014 Feb;243(2):290-8. doi: 10.1002/dvdy.24068. Epub 2013 Nov 26.
The three chick wing digits represent a classical example of a pattern specified by a morphogen gradient. Here we have investigated whether a mathematical model of a Shh gradient can describe the specification of the identities of the three chick wing digits and if it can be applied to limbs with more digits.
We have produced a mathematical model for specification of chick wing digit identities by a Shh gradient that can be extended to the four digits of the chick leg with Shh-producing cells forming a digit. This model cannot be extended to specify the five digits of the mouse limb.
Our data suggest that the parameters of a classical-type morphogen gradient are sufficient to specify the identities of three different digits. However, to specify more digit identities, this core mechanism has to be coupled to alternative processes, one being that in the chick leg and mouse limb, Shh-producing cells give rise to digits; another that in the mouse limb, the cellular response to the Shh gradient adapts over time so that digit specification does not depend simply on Shh concentration.
三个小鸡翅膀的趾代表了一个经典的形态发生素梯度指定模式的例子。在这里，我们研究了一个 Shh 梯度的数学模型是否可以描述三个小鸡翅膀趾的身份，并将其应用于具有更多趾的肢体。
我们提出了一个由 Shh 梯度指定小鸡翅膀趾身份的数学模型，该模型可以扩展到具有 Shh 产生细胞形成趾的小鸡腿的四个趾。该模型不能扩展到指定小鼠肢体的五个趾。
我们的数据表明，经典形态发生素梯度的参数足以指定三个不同趾的身份。然而，要指定更多的趾身份，这个核心机制必须与其他过程相结合，一种是在小鸡腿和小鼠肢体中，Shh 产生细胞产生趾；另一种是在小鼠肢体中，细胞对 Shh 梯度的反应随着时间的推移而适应，因此趾的指定不单纯依赖于 Shh 浓度。
