Science in Christian Perspective
The Role of Segregation In the Theory of Creation
WILLIAM J. TINKLE Ph.D.
From: JASA 4 (March 1952): 15-16.
As Doctor Barnes pointed out so ably at the Grand Rapids Convention, the way to combat a false theory is to build up a better one in its place. The theory of creation needs to be built up carefully and firmly, part by part, and this paper deals with one of the parts.
The broad meaning of segregation is a separation or moving apart of different sorts of things or entities. It is the opposite of amalgamation or fusing. In the genetic sense, in which the word is here used, it mean separation of characters which have been together in a plant or animal, so that in the next generation one of these characters is in one individual and the other in another. For instance a Shorthorn cow may be hornless and roan colored (roan being caused by a mingling of red and white hairs). A calf born to her this year may be horned and roan while another born later may be hornless and white; or a calf might be hornless and roan like the mother. In the first two examples of offspring there has been segregation of characters while in the third there has been none.
As an example in plants, consider garden pea seeds that are yellow in color and spherical in shape. Some of the offspring may be yellow and wrinkled, some may be green and spherical, while still others are likely to be like the parents, spherical and yellow. Again the first two examples illustrate a separation or segregation of characters that have been together but now are in different organisms.
It is readily seen that this diversity would not arise if there were no latent possibilities in the germplasm of plants and animals. The cow mentioned first had no horns yet she had had a potentiality for producing horns, as evidenced by the fact that horns appeared in some of her calves. Likewise the peas had latent hereditary factors for green color and wrinkled shape. These latent and recessive factors are not found in all organisms, but usually have come from a grandparent or more remote ancestor which had not only the hereditary factor but the actual character. An animal or plant that has such a diversity of hereditary factors is termed heterozygous. On the other hand there are some organisms that have no factors except for the characters they themselves manifest. If such peas are yellow and are mated with. yellow peas, all the offspring will be yellow. Such a germinally pure plant is termed homozygous.Biologists find these terms very useful, and while they are big words there are no shorter words with the same meaning. The word mixed may not mean the same as heterozygous, for we could have a mixture of kernels of yellow and white corn, both of which were homozygous for color.
Since every organism is a collection of many characters with a hereditary factor or gene for each, when characters segregate from each other they do not remain alone. They become members of new pairs or groups in the young plant or animal. Thus the term recombination of characters has about the same practical significance as segregation of characters. The words are not synonymous however, since one refers to the separation of traits and the other to the formation of new groupings in the next generation.
The best place to observe the above phenomenon is the offspring of organisms that have been crossed; but not so much the first filial generation as the second and succeeding generations. Crossing of varieties makes the first filial generation very heterozygous; and these plants or animals in turn, without further crossing, will manifest segregation and recombination of characters in succeeding generations.
It is possible to point out how this process is germane to the theory of creation, now that the process itself has been explained. We observe the heterozygous first filial generation segregating, thus giving rise to new combinations of characters, which we call new varieties. What if God created his creatures heterozygous in the first place? There is every reason to think that He did just that.
This means that in each kind of plant or animal created at the beginning there were a number of hereditary factors for traits that were not expressed in the original creatures, but since that time have expressed themselves by forming traits in the descendants of the original creatures. Thus in the people who were created there were hereditary factors for round heads, long heads, straight, curly, and kinky hair, various shades of skin pigmentation, high foreheads, sloping foreheads, supra-orbital ridges, and so on. Which of these traits originally were expressed and which were latent is unknown at the present time. In the original cattle were hereditary factors for red, black ' white, and other colors, a series of cumulative factors for milk production and another series for degree of beef type, etc. Lack of horns, called the polled character, seems to have arisen by mutation, which is different from simple segregation and will be explained below. In the original rock dove, if it be proved that from it have sprung all the domestic pigeons, were hereditary factors for fan tail, homing instinct, and others that are no less remarkable.
If organisms were created heterozygous in the first place the different potential characters would be sure to segregate out in succeeding generations. It is easily observed that inbreeding of heterozygotes gives rise to segregation; as for instance, mating animals of a first filial generation among themselves. Since we suppose that the Creator formed only a few of each kind of creature, of course the result was in breeding. Relatives had no choice but to mate with each other.
The occurence we are attempting to explain by this discussion of segregation is the appearance of varieties and breeds of plants and animals. It might be claimed (a) that these varieties have always been as they are now (b) that the environment developed them, (c) that they arose by mutation, or (d) that they are the result of segregation. The first suggestion is not tenable for many new breeds and varieties have been developed by man and others have appeared in nature. The second suggestion is that of J. B. Lamarck who said the giraffe got its long neck by stretching it to reach leaves of trees, and the duck developed the webs of its feet by stretching its toes apart. In this of course he overlooked the creation of diverse hereditary factors as well as segregation. This theory, known as the inheritance of "acquired characters" is in poor repute among the best scientists because it can not be made to work under observation. Different types of environment may indeed cause much diversity, especially among plants, but these changed characters are not passed on to the next generation and do not occur again unless the peculiar environment occurs again.
As for mutation, there needs to be an extensive study made to determine which characters have arisen by this process and which by the segregation of latent factors implanted at the beginning. Unquestionably the best known mutant characters are those that have arisen under observation in the laboratory and breeding plot. These are characteristically a loss of something, usually are negative entities, a majority are lethal, and few if any have been shown to enhance the welfare of the plant or animal. To be sure, a mutant character that is transmitted follows the law of segregation like any other, but at its beginning it arises de novo. The majority of the characters that make up our organisms do not bear the ear marks of mutation. Thus we conclude that it is not environment nor mutation but segregation of characters that is largely responsible for the observed diversity of varieties.
In the mind of the Creator there must have been some purpose in making provision for these changes in characters. While we can not be certain what that purpose was we can make a good estimate. His command was, "Be fruitful and multiply and replenish the earth." As the kinds of creatures spread to new regions, replenishing the earth, they encountered changed environments. A species that is perfectly uniform might become extinct in a new environment, while if it had segregated into different types one of these types might survive. From the standpoint of nature it is not so serious for individuals to die, since they can be replaced by progeny from the surviving stock; but if a whole species is wiped out it is lost forever.
In stating the theory of this paper the author makes no claim to originality but is merely voicing what is commonly believed by creationists. It is here explained in simple language for those scientists who are not trained in genetics.
In conclusion we are quoting Genesis 1:27 with a few words of clarification added: "And God created man in his own image, in, the image of God created He them;" heterozygous created He them.