Telegony

Telegony (Gr. Ti Xe, far, and y6vos, offspring), the name now given to the hypothesis that offspring sometimes inherit characters from a previous mate of their dam. Until recent years the supposed inheritance of characters acquired by a dam from one or more of her former mates was usually designated by breeders "throwing back"; by physiologists, "infection of the germ," or simply "infection." The doctrine of "infection," like the somewhat allied doctrine of "maternal impressions," seems to be alike ancient and widespread. Evidence of the antiquity of the belief in "maternal impressions" we have in Jacob placing peeled rods before Laban's cattle to induce them to bring forth "ring-straked speckled and spotted" offspring; evidence of the antiquity of the "infection" doctrine we have, according to some writers, in the practice amongst the Israelites of requiring the childless widow to marry her deceased husband's brother, that he might "raise up seed to his brother." Whatever may have been the views of stockowners in the remote past, it is certain that during the middle ages the belief in "infection" was common amongst breeders, and that during the last two centuries it met with the general approval of naturalists, English breeders being especially satisfied of the fact that the offspring frequently inherited some of their characters from a former mate of the dam, while both English and Continental naturalists (apparently without putting the assertions of breeders to the test of experiment) accounted for the "throwing back" by saying the germ cells of the dam had been directly or indirectly "infected" by a former mate. It is noteworthy that L. Agassiz, C. Darwin, W. B. Carpenter, and G. J. Romanes were all more or less firm believers in the doctrine of infection, and that a few years ago, with the exception of Professor A. Weismann, all the leading biologists had either subscribed to the telegony doctrine or admitted that "infection of the germ" was well within the bounds of possibilities. Even Professor Weismann did not deny the possibility of the offspring throwing back to a previous mate. The widespread belief, he admitted, "may be justifiable and founded on fact," but he was careful to add that "only the confirmation of the tradition by methodical investigation, in this case by experiment, could raise telegony to the rank of a fact." In assuming this attitude Professor Weismann decidedly differed from Herbert Spencer, who some years ago mentioned that he had evidence "enough to prove the fact of a previous sire asserting his influence on a subsequent progeny." The importance of determining whether there is such a thing as telegony is sufficiently evident. If a mare or other female animal is liable to be "infected" by her first or by subsequent mates, telegony will rank as a cause of variation, and breeders will be justified in believing (1) that pure-bred females are liable to be "corrupted" when mated with sires of a different breed; and (2) that inferior or cross-bred females, if first mated with a high-class sire, will thereafter produce superior offspring, however inferior or cross-bred her subsequent mates. If, on the other hand, "infection of the germ" is impossible, telegony will not count as a factor in variation, and breeders will no longer be either justified in regarding mares and other female animals as liable to be "corrupted" by ill-assorted unions, or benefited by first having offspring to a high-class, or it may be more vigorous, mate. Though, according to breeders, evidence of telegony has been found in nearly all the different kinds of domestic mammals and birds, most stress has been laid on instances of "infection" in the horse and dog families.

Telegony in the Horse Family. - Beecher at the end of the 17th century pointed out that "when a mare has had a mule by an ass and afterwards a foal by a horse, there are evident marks on the foal of the mother having retained some ideas of her former paramour, the ass." That mares used in mule breeding are liable to be infected is still widely believed, but irrefragable evidence of the influence of the ass persisting, as Agassiz assumed, is conspicuous by its absence. Darwin says, "It is worth notice that farmers in south Brazil. are convinced that mares which have once borne mules when subsequently put to horses are extremely liable to produce colts striped like a mule" (Animals and Plants, vol. i. p. 436). Baron de Parana, on the other hand, says, "I have many relatives and friends who have large establishments for the rearing of mules, where they obtain from 400 to l000 mules in a year. In all these establishments, after two or three crossings of the mare and ass, the breeders cause the mare to be put to a horse; yet a pure-bred foal has never been produced resembling either an ass or a mule." The prevalence of the belief in telegony at the present day is largely due to a case of supposed infection reported to the Royal Society in 1820 by Lord Morton. A chestnut mare, after having a hybrid by a quagga, produced to a black Arabian horse three foals showing a number of stripes - in one more stripes were present than in the quagga hybrid. The more, however, the case so intimately associated with the name of Lord Morton is considered, the less convincing is the evidence it affords in favour of "infection." Stripes are frequently seen in high-caste Arab horses, and cross-bred colts out of Arab mares sometimes present far more distinct bars across the legs and other zebra-like markings than characterized the subsequent offspring of Lord Morton's seven-eighths Arabian mare. In the absence of control experiments there is therefore no reason for assuming Lord Morton's chestnut mare would have produced less striped offspring had she been mated with the black Arabian before giving birth to a quagga hybrid. To account for the stripes on the subsequent foals, it is only necessary (now that the principles of cross-breeding are better understood) to assume that in the cross-bred chestnut mare there lay latent the characteristics of the Kattiawar or other Indian breeds, in which stripes commonly occur. Darwin and others having regarded Lord Morton's mare as affording very strong evidence in support of the infection hypothesis, it was considered some years ago desirable to repeat Lord Morton's experiment as accurately as possible. The quagga having become extinct, a number of mares were put to a richly striped Burchell zebra, and subsequently bred with Arab, thoroughbred and cross-bred sires. Other mares were used for control experiments. Thirty mares put to a Burchell zebra produced seventeen hybrids, and subsequently twenty pure-bred foals. The mares used for control experiments produced ten purebred foals. Unlike Lord Morton's quagga hybrids, all the zebra hybrids were richly, and sometimes very distinctly, striped, some of them having far more stripes than their zebra parent. Of the subsequent foals, three out of Highland mares presented indistinct markings at birth. But as equally distinct markings occurred on two pure-bred Highland foals out of mares which had never seen a zebra, it was impossible to ascribe the stripes on the foals born after zebra hybrids to infection of their respective dams. Further, the subsequent foals afforded no evidence of infection, either in the mane, tail, hoofs or disposition. Of the pure-bred foals, i.e. the foals by pure-bred sires out of mares which had never been mated with a zebra, two were striped at birth and one acquired stripes later - they were revealed as the foal's coat was shed. Moreover, while the faint markings on the foals born after hybrids completely disappeared with the foals' coat, the stripes on the three pure-bred colts persisted. One of the permanently striped colts, a bay, was out of a black Shetland mare by a black Shetland sire, one was by a dun Norwegian pony out of a roan-coloured Arab mare, while the third was by a Norwegian pony out of a half-bred bay Arab mare. It has been asserted by believers in telegony that evidence of infection may appear in the second though not present in the first generation. By way of testing this assumption, a bay filly, the half-sister of a richly striped hybrid, was put to a cross-bred Highland pony, and a Highland mare, while nursing her hybrid foal, was put to a colt the half-brother of a hybrid. The result was two fillies which in no single point either suggest a zebra or a zebra hybrid. Similar results having been obtained with horses and asses, there is no escape from the conclusion that the telegony tradition is not confirmed by such methodical investigations as were suggested some years ago by Professor Weismann (see Cossar Ewart, The Penycuik Experiments, 1899) Telegony in Dogs. - Breeders of dogs are, if possible, more thoroughly convinced of the fact of telegony than breeders of horses. Nevertheless, Sir Everett Millais, a recognized authority, has boldly asserted that after nearly thirty years' experience, during which he made all sorts of experiments, he had never seen a case of telegony. Recent experiments support Millais's conclusion. Two of the purest breeds at the present day are the Scottish deerhound and the Dalmatian (spotted carriage-dog), A deerhound after having seven pups to a Dalmatian was put to a dog of her own breed. The result was five pups, which have grown into handsome hounds without the remotest suggestion of the previous Dalmatian mate of their dam. A similar result was obtained with a deerhound first mated with a retriever. Many accidental experiments on telegony are made annually with dogs. Two such experiments may be mentioned. A black-brindled Scottish terrier belonging to a famous breed had first a litter of pups to a curly-haired liver-and-white cocker-spaniel. The pups were spaniel-like in build, and of a brown-and-white colour. Subsequently this terrier had pups to a black-brindled terrier. All the pure-bred pups were typical terriers, and evidence of their dam having escaped infection is the fact that three of them proved noted prize-winners. The subject of the second undesigned experiment was a wire-haired fox-terrier. In this case the first sire was a white Pomeranian, the second a crossbred Irish terrier. Having had ample opportunity of being "corrupted," the fox-terrier was mated with a prize dog of her own strain. The result was three pups, all in make and markings pure terriers, and one of the three was regarded as an unusually good specimen of the breed.

Experiments with cats, rabbits, mice, with sheep and cattle, with fowls and pigeons, like the experiments with horses and dogs, fail to afford any evidence that offspring inherit any of their characters from previous mates of the dam; i.e. they entirely fail to prove that a female animal is liable to be so influenced by her first mate that, however subsequently mated, the offspring will either in structure or disposition give some hint of the previous mate. In considering telegony it should perhaps be mentioned that some breeders not only believe the dam is liable to be "infected" by the sire, but also that the sire may acquire some of the characteristics of his mates. This belief seems to be especially prevalent amongst breeders of cattle; but how, for example, a long-horned Highland bull, used for crossing with black hornless Galloway cows, could subsequently get Galloway-like calves out of pure Highland heifers it is impossible to imagine.

In conclusion, it may be pointed out that it was only natural for breeders and physiologists in bygone days to account for some of their results by the "infection" hypothesis. Even now we know surprisingly little about the causes of variation, and not many years ago it was frequently asserted that there was no such thing as reversion or throwing back to an ancestor. But even were the laws of heredity and variation better understood, the fact remains that we know little of the origin of the majority of our domestic animals. On the other hand, from the experiments of Mendel and others, we now know that crossbred animals and plants may present all the characters of one of their pure-bred parents, and we also know that the offspring of what are regarded as pure-bred parents sometimes revert to remote, it may be quite different, ancestors. The better we understand the laws of heredity and variation, and the more we learn of the history of the germ cells, the less need will there be to seek for explanations from telegony and other like doctrines. (J. C. E.)