CLUE TO HEREDITY

Evening Star, Issue 19763, 13 January 1928, Page 8

CLUE TO HEREDITY

EXPERIMENTS IN A MONASTERY GARDEN Johann Mendel was the sou of a crofter in Austrian Silesia, and he was born in 1822 in the same year as Francis Gallon (writes Sir J. Arthur Thomson in ‘ John o’ London’s Weekly). It gives one pause to learn that two of the three men who laid the foundations of the modern science of heredity—Gallon, Mendel, and Weismann—were born in the same year. Weismann was horn twelve years afterwards, PEASANT ANCESTRY. Mendel was one of the many groat men who have sprung from a peasant ancestry, and have succeeded in life, in face of difficulties, by brains and force of character. His father held his little farm on condition of rendering some agricultural service to the lord of the manor, and there was certainly no superfluity of goods; It is touching to road that Mendel s sister voluntarily snrrended part of her dowry so that Johann might be sent to a school at some distance—a sacrifice afterwards generously repaid, for Mendel saw to the education of her three boys. , In early years, when there was no school at all" in the village, Mendel had simple lessons from an uncle who held private classes, so gladly would ho teach. The hoy’s promise was such that, as we have said, an effort had to be made to give him a wider education—an effort which was abundantly justified. In biographies wo often find some unusual influence or even impression that gave a trend to the subsequent life; and in Mendel’s ease that is surely to be found in the fact that his father was greatly interested in fhe cultivation of fruit-trees, and taught his hoy the art of grafting. The boy is father of the man; from grafting to crossbreeding is but a step. IN THE MONASTERY. The photographs of Mendel show a fine forehead, a big brain, keen eyes, and firm lips, with a general suggestion of kindly obstinacy. His abilities seem to have' attracted the attention of the clergy, and when he was twenty-one he became a monk in the monastery of Briinii, with a view to wider educational service. When he was ordained a priest he took the “ religious '* name of Gregor. , , , T'-un 1861 to 1853 he, attended, at the cloister’s expense, the University of Vienna, where he studied sciencemathematics and physics in particular. Returning to the monastery, lie became teacher of science in the town-school or • “Gymnasium,” and a marked success he seems to have been. This continued till 1868, when he was promoted to bo Abbot or Prelate of the cloister. He held this responsible office till lie died, in 1884, two years after Darwin. From the scientific point of view the fruitful period of Mendel’s life was during the ten years or so before he became Abbot. For it was then that he made his famous experiments on peas in the cloister garden. The exjHjriments on edible peas lasted for about eight years, and they were supplemented by studies on sweet-peas, hawk-weeds, and bees. Of this prolonged experiments on crossing different races of honey-bee no record has been found, which is a matter for keen regret. THE LAW OF HEREDITY. ]n 1886 he published the famous papey on peas, in which lie established the law of heredity known as Mendel’s Law, and also suggested its explanation. But for some inexplicable reason the paper, published in the Proceedings of the Natural History Society of Bninn, failed to attract attention. Only one naturalist of distinction, Nagcli, _ seems to have known of it. and he did not discern its importance. It was an extraordinary irony of fate that a discovery of the first magnitude, which Darwin would have welcomed with an open mind, was smothered at birth.

In 1900 Mcndclian inlicritnncc _ was re-discovemi by three botanists independently, De Vries, Correns, and Tschermak, and soon afterwards the important work of Bateson showed bow much Mendelism meant for the young science of genetics. it is difficult to understand bow Mendel’s papers were ignored. In part it seems to have been a piece of ba!d luck, but it was also due to the lack of an International Information Bureau. Mendel discovered that certain kinds of characters (“unit characters”) behave in a particular way in inheritance. They do not blend or break up or average’off, but persist in their intactness in a certain percentage of the offspring, generation after generation. If a purebreeding, tall-growing variety of pea is crossed with a puro-breeding dwarf variety of pea, all the offspring are tall; and we say that tallness is a dominant character and dwarfness recessive.

But in the progoncy of these hybrids there are three tails to one dwarf, and of every three tails ono is purc-breeding, while two are like their immediate parents and will produce tails and dwarfs in the three to one ralio. THE MENDELTAN CLUE.

If a grey mouse is crossed with a white one, all the offspring are grey. If those greys pair among themselves or with others of the same history, their progency will show on an average, in a litter of, say, four, ono purohreeding grey, one pnre-breeding white, and two which look grey, hut have the character of whiteness latent, as subsequent breeding shows. The Mendel in n cine enables the breeder and cultivator to combine useful characters, for instance, of wheat or poultry, in a rapid, secure, and economical way.

Mendel must have known how big his discovery was, and the disappointment of being ignored must have been severe. But he used to say; “My time will come ” ; and though ho did not see the reward of his labors his confidence had been thoroughly justified.