MUTATION IN HUMANS.

Otago Daily Times, Issue 20961, 26 February 1930, Page 15

MUTATION IN HUMANS.

A CLAW-FINGERED FAMILY.

.A mutation is a sudden/ and unexpected divergence of an individual of a species from the standard type. For instance, if gardeners had observed for many generations that all the petals of all the flowers of a certain species were always white and never any other colour, the sudden appearance of pink flowers in this species would be a mutation. If sonn or all the seeds from this flower pro dnced plants with pink flowers or plants which, although white themselves, ' gave rise by suitable breeding to some pink flowers in the next generation, we would have a heritable mutation.

Mutations of this kind happen from time to time in various species of plants and animals. Numerous cases are known of deformities in man which affect the hands and feet originating as. mutation* and showing dominance to normal conditions in inheritance.

A new mutation, affecting the nails of the fingers and toes came to light in a certain family some time ago. The case under consideration is that of a man, a native of the Philippines, married, and having nine children. His nails are claw-like. His parents and grandparents, uncles, aunts, brothers, cousins, nephews, and nieces are/ 1 all free of this abnormality, and careful search failed to reveal any record of a similar abnormality. A cross-section of a normal nail, as can Vbe determined by looking at , the finger-tip while pointing it toward the eye, is a simple arch, while that of the claw-nail is somewhat rounded and solid. It is not only ugly to look at, but has certain definite disadvantages. These nails are always kept very long, becauscloser cutting is painful and difficult; Walking or running is considerably im peded, becuse the toes hurt whenever full pressure is put to bear upon them. Of his nine children, four boys and fivgirls, five are similarly affected, three boys and two girls. We have henclearly a heritable mutation which is a scene in the drama of evolution. If the mutation were advantageous to those affected by it so that they could com pete more favourably in the struggle for existence with normal people;, in the course of a number of generations this mutation 1 might establish itself very thor oughly in a certain section, and we would have ultimately a tribe or race of claw nailed people. As this mutation is unfavourable rather thru favourable, it would possibly or probably die out in a state of natural keen competition.