As of 2004, no definitive conclusions had been reached, although a Mendelian pattern of inheritance is suspected.
Online Mendelian Inheritance in Man (OMIM).
All these principles are consistent with Francis Galton's law of particulate inheritance in heredity, and with the modern doctrine of " unity of characters " held by students of Mendelian phenomena.
The proportions in which the various coloured individuals appear are approximately those demanded by the Mendelian principle of gametic purity and segregation.
Castle has shown, with Mendelian expectation.
The operation of Mendelian processes in human heredity is further shown by the close relationship that exists between the appearance of albinoes and cousin marriages.
And, when the whole facts are borne in mind, there can be no reasonable doubt that the Mendelian principles offer an intelligible solution of the problem.
It is equally clear that there is a broad analogy between the kind of characters on which systematists often have to rely for the separation of species and those which Mendelian workers have shown to behave in accordance with the Mendelian theories of mosaic inheritance with segregation.
It is to be noticed, however, that the Mendelian conceptions are in no sense an alternative to Darwinism; at the most they would serve to assist in explaining the mechanism of variation, and by enlarging our idea of the factors, increase the rate at which we may suppose selection to work.