by Sara, Gr.6

..How it all started...

Genetics have been with us since the

beginning of time. Every person on the

planet(and quite possibly on other

planets) has genes, even though they

have only been recently discovered

(recently in terms of how long humans

have been around). Genetics was

mentioned in the Bible, too! Also,

several Greeks also had theories about

heredity and why children resemble their

parents. Hippocrates recognized that

the male contribution to a child's

heredity is carried in the semen. He also

thought women had some similar fluid,

and that the two fluids fought each other

for traits, like the finger part of the man's

and woman's semen fought each other,

and which ever semen won send that

parents trait to the fingers.

Gregory Mendel (1822-1884), the

discoverer of the gene and the founder

of genetics was an Augustian monk

from Brunn, Austria. In his spare time,

Mendel bred pea plants in the

monastery gardens. Many pea plants

had many different traits, like some were

were tall, some were short, some peas

were smooth, others were wrinkly, etc.

Mendel then tried to make hybrids. He

did this by snipping the male part of the

plant to prevent "selfing" (pea plant can

fertilize themselves). Then he dusted

the female part with the desired "father."

Then he tied bags over the flowers to

prevent stray pollen from getting into the

flowers. Thus, he was able to control the

parentage of each generation. His first

discovery was that tall plants plants

crossed with short ones produced tall

ones, not medium ones. He then

concluded that some genes were

dominant and some were recessive.

When he raised hybrids though, he

found about 1/4 of them were short, but

the other 3 were tall. He then concluded

that genes are made of two distinct

types, or alleles. A plant may have the

same or different alleles (AA, aa, Aa).

He found that hybrids can have small

offspring, but if a plant with all dominant

alleles are crossed with plants that have

all dominant genes, all the offspring will

have the dominant alleles (the same can

be said for recessive too). It wasn't until

1900 when Mendel's works were

actually noticed. Three men working

independently, Hugo DeVries, Erich Von

Tsohermark and Carl Correns did some

experiments and came out with the

same results as Mendel. They didn't

take credit for it, but announced that

Mendel had had the same results and

had done such testing first.

A Conclusion

Now as you can see, Genetics has quite a

history! Now you know that Mendel wasn't the

first person to discover genetics. Now, in the next

section we will learn how these genes work!