College of Cat Genetics: Part XVI
by Patricia Turner
Study Unit 16
Earlier articles have explained that mutants reported in the cat can be studied through breeding records and pedigrees in order that the mode of inheritance can be ascertained. Studies are made by the collection of facts through observation, and facts can be defined as observations that can be confirmed by other people. A researcher must be able to repeat the matings from which he has obtained his facts and these matings must also be repeatable by other researchers or breeders.
Observations include all information obtained through the senses, or through scientific instruments such as microscopes which are extensions of the senses. Information which can be said to be fact (as above) becomes data and the collection of data is the foundation on which all research into genetics is based.
Generally speaking, breeders have no difficulty in agreeing upon the facts, i.e. how many kits in a litter, what sex, what colour, etc. However, the point where controversy may arise is when the facts are interpreted. When a genetic researcher interprets facts, he usually does this in the light of a particular hypothesis.
Genetic research is like detective work and the geneticist, like a detective, is continually working with a view to solving problems. Einstein said that before solving a problem the situation must be investigated and the facts of the case collected. The creative part of the work of a genetic researcher comes when he makes a suggestion for the solution of the problem. Suggestions, or tentative solutions, have to account for all the known facts and should also predict what other events have happened or will happen. Such a tentative solution is called a hypothesis. On the basis of his hypothesis the genetic researcher looks for further clues. If the new clues tend to support the hypothesis then that hypothesis is said to be strengthened but if they tend to contradict it then the hypothesis must be revised or even discarded. It is not unusual for a number of hypotheses to be tested before a solution to the problem is found.
Probably the formation of a hypothesis is the most creative activity in a science--a great many hypotheses have been said by their originators to be lucky guesses or hunches though extensive background knowledge is obviously necessary in order to form the hunch.
Some researchers use the word theory instead of hypothesis, but the definition generally accepted is that a hypothesis describes the initial attempt to solve the problem and that if it stands repeated testing it may be called a theory.
So, firstly, a hypothesis must explain the problem and account for all the data related to the problem. Then it must explain the relationship of the data to the problem and, most important, it must lead to the prediction of new information. If experiments subsequently confirm the prediction, then the hypothesis gains support.
A hypothesis must be tested by experiments (if in the case of genetic research, by test matings), and as new data is predicted it must be confirmed through observation and test matings. Controlled test matings attempt to make certain that only one problem is being tested at a time.
"Experimental Breeding" have become dirty words in the cat fancy mostly because of the "trial and error" methods adopted by some of its members, reminiscent of the medieval alchemists trying to produce gold. "Trial and error" methods are usually known as empirical, their procedure being based almost entirely upon observations of experiments made where hypotheses are not used. Thus empirical knowledge can be said to be that gained through direct observation. As a method, emprilcalism has little to commend it and is usually a slow and unsuccessful process not be recommended unless there is no other alternative.
True experimental breeding--test matings based on hypotheses for a particular problems--is quite different and its results can confer great benefit on the fancy. Therefore, to consider any one problem in cat genetics, it is necessary to collect facts which can be repeated and verified. The controlled test mating is important in the testing of a hypothesis.
Having considered the importance of controlled experiment whenever possible, the fact that the raw material for genetic knowledge of the cat is the cat himself immediately draws attention to the fact that some matings are not planned by the breeders and that the results are often useful as extra facts which can help prove or disprove hypotheses on which controlled test matings may also be made. Therefore, while there is little to commend in the mating of two cats from different breeds or with different characteristics just to see what will happen, details of matings made accidentally between such cats become invaluable data in the hands of experienced genetics researchers and can often form the basis on which a hypothesis may be made.
It may seem odd that the biggest contribution towards an understanding of cat genetics has been made by the mouse. The mouse, which breeds quickly and easily, is one of the most popular animals for biomedical research and thus provides the largest amount of breeding data likely to be accurately recorded.
The mutant genes of the cat have largely been perpetuated by cat fancies rather than geneticists, but when information on mammalian species is compared it is at once seen that the variations reported in the cat are often similar in methods of inheritance or effect or both to those already studied on the mouse.
Thus, a study of mouse genetics is both practical and valuable for the genetic researcher and can often give a startling point of study for a problem in the cat.