Genetics

Kids Corner

What is genetics?
Genetics & rolling your tongue
Genetics & eye color
Genetics & pea plants
Experiment with beans 

What is genetics?

The scientific definition of genetics is: the branch of biology that studies the ways in which hereditary information is passed on from parents to offspring.

But...our definition of genetics is: the way scientists study how the stuff in you came from your parents.

Every person has 23 pairs of chromosomes which are made up of genes. You get half of your chromosomes from your mom and half from your dad. Your chromosomes contain the recipe that makes you -- Y O U !

Genetics and rolling your tongue...

Can you roll your tongue? If you can or not depends on your chromosomes. Rolling your tongue is the dominant gene or big "R".

Not being able to roll your tongue is a recessive gene or small "r".

If you can, your tongue rolling gene is either "RR" or "Rr". This means that at least ONE of your parents can roll their tongue (had a big "R").

If you can't, your tongue rolling gene is "rr". This means both of your parents gave you a little "r".

For fun, find out how many people in your family can roll their tongues!

Genetics and eye color...

What color are your eyes?  If they're brown, your eye color gene is dominant or big "B".  Then your eye color gene would be either "BB" or "Bb".

If they're blue, your eye color gene is recessive or little "b".  Then your eye color gene would be "bb". Here's an example of how that might happen...

With three sets of two brown-eyed parents:

Dad "BB"
Mom "Bb"
"B"
"B"
Kid "BB"
(brown-eyed)
 
Dad "BB"
Mom "Bb"
"B"
"b"
Kid "Bb"
(brown-eyed)

Dad "Bb"
Mom "Bb"
"b"
"b"
Kid "bb"
(blue-eyed)

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There are more than just two genes that make up eye color. This is just one simple example to give you an idea of how you get your eye color.

Genetics and pea plants...

In pea plants, the tall gene is dominant ("T") and the short gene is recessive ("t").

If someone is growing pea plants and wants to have only tall plants, they can do two things. Either, buy all tall plants ("TT") OR take the pollen of the tall plants and put it on the pistil of the short plants to get ("Tt") . This will make a tall pea plant even though it will have one short ("t") gene.

Experiment with beans...

Here's a FUN experiment to try at home to show that the dominant characteristic is more likely to appear than the recessive characteristic.

You will need the following things:
2 paper bags
10 brown bean seeds
10 white bean seeds

In our example, the dominant characteristic is brown (" BB " or "Bb ") and the recessive characteristic is white ("bb").

The characteristic is made up of two genes, one from each bag.

The brown bean seeds will be the gene for the dominant color brown ("B"). The white bean seeds will be the gene for the recessive color white ("b").

Label one paper bag "A" and the other "B". Put the brown beans in bag "A" and the white beans in bag "B".

Take one bean out of each bag. 

Make a table to record the combinations you pull from the bags. Repeat this nine times.

Next, empty both bags and put 5 brown beans and 5 white beans in bag "A".

Do the same for bag "B".

Take one bean out of each bag.

Make a table to record the combinations you pull from the bags. Repeat this nine times.


Now, compare your results! 

What would the seed color be if both beans were brown?
Answer:   BROWN "BB"

What would the seed color be if both beans were white?
Answer:   White "bb"

What would the seed color be if one bean was brown and the other was white?
Answer:   Brown "Bb"