Summary:
A brief overview of genetics and heredity. A rapidly growing field of science, genetics benefits greatly from the work of Gregor Mendel, considered the "father of genetics."
Did someone ever tell you that you have your mom's eyes? Your dad's nose, maybe? You may notice that some of your physical and behavioral features are quite similar to those of your parents. How do children inherit characteristics of their parents? The answer is simple: genetics. To be more specific, the genes for many traits are passed down in families from parents to children. A basic principle of genetics contributes to this: the principle of "segregation."
The principle of "segregation" works for both plants and animals alike. Since everyone comes from two parents, they inherit half of their traits from their mother and half of their traits from their father. Therefore you will have two "alleles," or for each gene, one from each parent. Because of this, your body "expresses" that gene.
However, there is one problem with this principle. What if there are two alleles that say different things? For example, if one parent has freckles and the other doesn't, which trait would be passed down to the child? The dominating gene would be passed down, meaning one of the alleles dominates over the other. Regardless of the parent that the gene came from, certain genes will dominate. For instance, in the case of freckles, if one has freckles, they have the dominant gene (F-). If they do not have freckles, they are recessive. For a child to inherit a recessive gene, both of their parents must carry that recessive gene. Evidently, having a dominant gene is much more common, since a recessive gene must be carried through from generation to generation.
There are several other difficulties with heredity, however. A child can have an unexpected trait when a mutation, or change in the DNA occurs. A mutation can sometimes occur for no reason at all, or sometimes because we are exposed to certain things in the environment, such as cigarette smoke or harmful chemicals. While most mutations are not detrimental, some have detrimental effects and can cause people to be more prone to certain diseases or problems. Our cells have "repair kits" to fix most mutations to keep them from affecting us, but unfortunately, sometimes these "repair kits" don't work as well as they should.
The field of genetics would be nothing without the work that geneticists do. One of the most famous of them is Gregor Mendel, who is known as "the father of genetics." The Laws of Inheritance were created after he conducted numerous plant hybridism experiments. Between 1856 and 1863, he cultivated and tested over 28,000 pea plants. His experiments brought forth two generalizations: Mendel's Laws of Heredity or Mendelian inheritance. These are described in his paper, "Experiments on Plant Hybridization." Although he was not well known in his time, his discoveries were found to be extremely beneficial to the field of heredity and genetics. Thanks to the work of geneticists, this field of science is growing rapidly.
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