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Genetics 101

by Rev. John Parks
         Children are usually like their parents in many ways. You have no doubt heard the expression “like father, like son” and have unconsciously accepted it as being true. It might be a grave mistake to forget mother though, because she has a part in determining the nature of the offspring too. To ignore her would be the same as if ignoring fifty percent of the facts.

If we are to take advantage of the laws of heredity, we must know what they are, so this month we are going to delve into some of these laws. Hopefully, it will lead to a greater awareness of genetics at work.

One of the first things to look for in your hounds is the existence of variations. If every Beagle for example, was black and tan in color, we would not be able to learn much about color as markings. Fortunately, this is not the case, so it gives us something to study.

The same thing is true of numerous other characteristics, which vary greatly in Beagles. Therefore, we can study them and learn more about heredity from them.

A long time ago, a man name Gregor Mendel studied differences within plants, and he came up with certain genetic laws or principles, which can guide us in our study of heredity. At the age of twenty-one, he entered a Monastery in Briin, Moravia, and spent the rest of his life studying God’s wonderful world.

Gardening was one of Mendel’s loves. In a little garden behind the Monastery, Mendel conducted many simple experiments. The results of these experiments were recorded in a daily journal. Besides the garden experiments, Mendel experimented with mice in his rooms, bees at the edge of his garden, and even the farm animals nearby.

Some writers contend that Mendel chose this type of life for economic reasons, rather than because of his dedication to God. I will leave that to students of history to decide. He was elected to an office of leadership in his later years, and his experiments diminished as a result of this greater demand on his time.

Mendel experimented with garden peas, snapdragons, pumpkins, beans, violets, four-o-clocks, corn, and many other plants. His early work with garden peas was very revealing though.

In garden peas, he observed many contrasting characteristics. These included smooth vs. wrinkled seeds, yellow cotyledons vs. green cotyledons, inflated pods vs. constricted pods, yellow pods vs. green pods (when unripe), flowers on the ends of stems vs. flowers in the axils of the leaves, transparent seed coats vs. brown seed coats, and tall plants vs. dwarf plants. This first step in analyzing inheritance was the observation of clear differences between individual plants within the same species.

The next step for Mendel was the crossing of individuals that differed to see what the results would be. He always crossed opposites so he could see the results more clearly.

In one experiment he crossed tall with dwarf plants. In the first generation, the offspring were all like the tall parent. The he crossed two of these tall offspring to produce a second generation. The resulting plants appeared to be tall three-fourths of the time and dwarf one-fourth of the time. Therefore, Mendel called the tall characteristics a dominant characteristic. He concluded that tall is dominant over dwarf and he called dwarf a recessive trait.

Here is how we could sketch this graphically (let’s use the capital letter for a dominant factor – T for tall and s small letter for recessive factor-d for dwarf.)

PICTURE WILL BE INSERTED HERE SOON

This shows Mendel’s law of segregation.

            There are two other terms that arose from Mendel’s experiments that should be noted here. The first is homozygous. Homo means “the same as.” The other term is heterozygous. Hetero meaning “different” or “differing.”

            Note in the previous graphic that TT and dd would be homozygous and Td would be heterozygous.

            If your hound has a lot of genes that are the same, it is probably homozygous for those traits. However, you can’t tell if it is homozygous for many traits or heterozygous unless you bred it. Even then you can’t tell for sure because it depends on the hound it is bred to.

            So, what is the use in studying genetics? Well, believe it or not, it does help. It is both fascinating and frustrating.

            There are many factors to keep in mind when you breed Beagles. I will discuss some breeding methods in our next visit. Be sure to be with me then. Meanwhile, enjoy this great magazine and the best Beagle website on the internet. Please, take a few minutes and order my book Breeding Better Beagles and you will be a leg up on this.

Should you have a concern regarding the health of your Beagle(s), you should contact your veterinarian. All information on this site is presented solely for educational and informational purposes and should not, at any time, be considered a substitute for seeking or receiving veterinary care for your Beagle(s).