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.
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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.
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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. |
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. |
Gregor Mendel combined logic and math to build the Theory of Inheritance |
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. |
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(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!!! |
1. 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. |
2. 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. |
3. 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.. |
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. |
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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. |
A younger Gregor Mendel in his early 30's at the monistery. |
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. |
Questions then e-mail me at geneticsrus@yahoo.com |
Also, check out Howstuffworks! This guy named Marshall Brain has created a business
that explains how things works. The material is presented in a cool, and easy
manner that makes it one of the most popular sites around. |
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