Where are My Genes?
So what do ya think?? How am I doing? Do you like Genetics R Us. Well if you do, then I hope that you will continue to enjoy my website. We will now begin part two of Genetics R Us. In this part, we will learn about the gene. The best way to learn about the gene is to learn about how it was discovered, and the person responsible for it’s discovery. Like all sciences, genetics has its roots in the minds of curious people who loved to poke around. Let’s meet an individual that loved to poke around in his garden, Gregor Mendel.
Genetics has its beginnings in the flower garden of an Augustine monk by the name of Gregor Mendel. Mendel loved to poke around in his flower garden to discover new things. Like many of his day, Mendel questioned the similarities between parents and children.
Gregor Mendel (1822-1884), an Augustine monk that lived in the 19th century, performed the first set of experiments on plants that marked the beginning of the science known as genetics.
Mendel was determined to find out what parents passed on to their children. Why do kids resemble their parents or grandparents? This is something that humans have tried to answer for thousands of years. Mendel thought that he could answer the question above, by experimenting with plants. In particular, Mendel worked with flowers and peas that were present in his garden at the monistery where he lived. Let’s repeat some of Mendel’s experiments, so we can see what he accomplished. Let’s first began by looking at a typical flower.
Here’s a typical flower shown toward your right. Like humans, there are female and male flowers. The petal is the part of the flower used for display. The pistal is the female sex organ. The stamen is the male sex organ. Flowers have children in the same manner as people do.
Here’s how it works. The pistil has egg cells inside it. The stamen produces a sex cell called pollen. Through many ways, the pollen cell is transfered into the pistil where the egg cells are located. Eventually a single pollen cell fertilizes an egg cell, and the flower produces children. When this happens, it is called self-fertilization.
In nature, plant self-fertilization is something that happens quite a lot. Flowers that have both female and male sex organs within the same flower are called monoecious plants. Gregor Mendel used these type of flowers in his experiments. With that in mind, let’s begin to take at look at what Mendel did.
Mendel looked at certain physical characteristics of flowers he used. Basically, Mendel would mate two different flowers and then look to see if that feature was present in the children. Next, Mendel would then mate the children with each other to see if that same feature was present in their children.
For example, in his first experiment, Mendel studied flower color. He mated a white flower with a pink flower. In order that the pink flower did not self-fertilize, Mendel cut the stamen of the pink flower. What Mendel noticed next surprised him!!!!!!
To Mendel’s surprise, the children of both parents were all pink!!!! Not a single flower was white!! In other words, the white color has skipped a generation. This happens in the human world. You may have noticed features your parents have, but you don’t.
To make things easier for you, you can refer to the children as the first generation, or (F1). Mendel didn’t stop here. Like a true scientist, Mendel continued to dig deep for the answers he was looking for.
In his second round of experiments, Mendel continued to track the color of the flowers he used. Mendel took two of the new child plants, and then mated them together. To his surprise, the white colored flowers reappeared. The white color skipped a generation and reappeared in the second generation.
Mendel was completely surprised by these observations. What could possibly explain what he had saw. In science, a theory is a true explanation for a set of observations that one sees in nature. Before Mendel could put together a theory to explain what he saw in his garden, he decided that he should work with other types of plants. In this way, with more similar and consistent observations across different plants, Mendel could construct a solid scientific theory.
Here’s a summary of other plants Mendel used in his work. Mendel used peas, seeds, and other plants. More importantly, Mendel studied other phyiscal plant traits such as seed shape and color. Mendel looked a plant height and flower position.
In total, Mendel studied and experimented with seven plant traits. In each case, Mendel noticed the same consistent patterns in his experiments. Let’s take quick review of what Mendel discovered.
In his first observation, Mendel saw no blending of traits. If a puffed pea plant was mated with pinched pea plant, there was no mixture of traits such as a puff-pinched pea plant.
In his second observation, Mendel noticed only one trait that was present in the children. If a green pea was mated to a yellow pea, the kid peas were all green.
Mendel’s final observation was that a trait can skip one generation and reappear in another generation. Also, Mendel noticed that the disappearing trait would reappear in 25 percent of the flowers or 1 out of every 4 flowers.
Gregor Mendel combined logic and math to build the Theory of Inheritance.
Mendel began to sit down to construct his scientific theory to explain what he saw in his garden. He worked long and hard. The result of Mendels hard work paid off when he created the theory known today as Mendel’s Theory of Inheritance. Let’s see what this scientific theory is.
In order to make everything run smooth, Mendel created and defined what is now known today as the gene. In Mendel’s view, a gene was a single unit of inheritance that parents pass on to their children. Today, we know a gene is much more than what Mendel first thought. Remember, Mendel knew nothing of DNA, cells, and proteins. You, however, are armed with much knowledge about DNA, cells, and proteins. So it’s quite understandable what Mendel believed. Just put yourself in his shoes.!!! Now let’s finally take a look what Mendel’s had to say.
Mendel’s Theory of Inheritance
(Better known as Mendel’s Three Laws Of Inheritance)
Gregor Mendel’s Theory of Inheritance actually consists of three laws. In science, a law is a statement that describes how nature behaves under a certain set of circumstances. Here are the laws!!!
- This law basically says that if two different parents which each have a different trait mate, then only one of those traits will be seen in the children. Mendel figured that a child has to get at least one gene (unit of inheritance) from each parent. The gene that is dominant is one that is seen in the child. This law explains why Mendel only observed green peas when he mated a yellow parent with a green parent. The green trait is dominant.
- This law has to do with how the genes are passed into the sperm and egg cells. Sperm and eggs cells are special cells because they each have one of every gene. When a parent produces a sperm and egg cell, one of every gene is placed into a sperm or egg cell. When these cells fuse to form a new life form, the child has a gene from each parent.
- The third law is sometimes hard for some people to grasp and understand. It basically says that when a parent produces a sperm or an egg cell, of the two genes that the parents have, one of those genes are randomly placed into a sperm or an egg cell. Let’s say that you have a pink flower that has two genes for petal color. One of those genes gives the flower a pink color. The other gene would give the flower a white color. If the pink gene is dominate, the flower will display a pink color within its petals. Let’s say now that this flower produces sperm cells. This male flower could produce millions of sperm cells that all contain a pink color gene. Or this same flower could millions of sperm cells that each contain a white color gene. Or the flower could produce millions of sperm cells that each contain a white color gene and a pink color gene at the same time. It doesn’t matter. Genes are randomly placed into sperm and egg cells with no rule that controls them..
A younger Gregor Mendel in his early 30’s at the monistery.
And there you have it. The world according to Mendel. (Well, the world as far as inheritance is concerned at least!!) Gregor Mendel, like Watson and Crick, has earned his place in history because his work was a platform that provided a key to unlock the secrets of inheritance. A secret that has eluded humans for thousands of years.
Mendel’s dedication and persistance for answers is something that is quite rarely seen. Mendel’s cleverness and creativity allowed him combine mathematics and observations to produce the still used theory of inheritance. Today, we know a lot more than Mendel did! Mendel knew nothing about DNA, cells, and proteins.
Genetics is taught in virtually every high school and university on the earth. Modern genetics is still based on the laws discovered by the 19th century monk, Gregor Mendel.
On the other hand, we know about DNA, cells, and proteins. Therefore, our modern understanding of genetics is quite different from what Mendel thought. In the next section of Genetics R Us, we are going to look at what the gene is from the current modern standpoint. So get ready!! Put on your seatbelts, as Genetics R Us is about to really take off.