Mendelian Genetics -- Pea plants, Crazy Plant Shops, Lemmings, and Dragons!

This week, we went further into genetics, using several games.

This game was a second game about Mendel's pea experiments.

We looked at seven traits that Gregor Mendel observed in his pea plants, and did breedings of various plants to see what happened.  Mendel was the Swiss monk whose experiments with pea plants formed the foundation of genetics.  Genetics is the study of how traits and diseases are passed from one generation to the next.

We discussed the difference between a trait that can be inherited and a disease that can be inherited.  A trait is a characteristic of an individual that we can notice (like Aaron O.'s ginger colored hair), is caused by something in his DNA, but doesn't appear to cause death, disease, or other harm (such as an enzyme not being able to function normally).  An inherited disease is when something in your DNA, often just in one gene (specific part of your DNA) is different in a way that causes a disease, usually because a protein doesn't work properly.

An example we talked about was sickle cell anemia.

There is a gene that for some people doesn't work properly because it has a mutation (a change in the DNA compared to most other people).  People who have the mutation have blood cells that don't quite look normal, they are squished and shaped like a sickle.  This makes it so their blood doesn't carry oxygen as well, and sometimes the people with this disease have episodes where they have to be hospitalized.  This disease is more common in certain parts of Africa than it
is here, specifically in areas where malaria is common.

We all have two copies of every gene, one from our mother and one from our father.  People who have sickle cell anemia got two copies of the mutated gene, and that's why they're sick.  People who have one copy of the mutated gene and one normal gene don't have the disease and are called carriers (because they carry the mutated gene).  What researchers have discovered is that carriers of sickle cell anemia are protected from malaria.  They get much less sick from malaria than people with normal red blood cells.  They think that's why the mutated gene (which can cause sickle cell anemia) is common in parts of Africa.

Next, we moved onto a game called Crazy Plant Shop,

and you can play the free version even though it's part of a paid service called BrainPop.  In the game, you own a plant shop, and Gregor Mendel talks you through buying plants from a catalog, breeeding them together to get the plants that people order, and then fulfilling the orders.  You get new plants and traits and see how Punnett squares work.  We could see from the Punnett squares what the chances were of getting the plants we wanted, and could choose to let probability decide or use our machine to get what we wanted for sure.  We saw that even when the chances were 75% for getting the one we wanted, sometimes we didn't get it.

Then, we looked at a game called Phylo, which is a game

that uses the players to further scientific research.  Humans are actually better at recognizing patterns than computers, so the computers take DNA sequences from different species and turn them into sets of colored boxes for us humans to line up.  When we line up all the colored boxes so they match as best we can figure, we have helped come up with information about how the different species are related for the particular gene.  We could see that work is being done with several important cancer genes, and playing the game generates valuable scientific data that is actually used!

Lastly, we played a genetic game about lemmings, to
better understand Punnett squares.  In this game, we looked at the gene for albinism, which is a lack of pigment (coloration) in the hair, eyes, and skin.  It is a recessive gene, which means it could hide out.  An animal could have one normal gene and one albinism gene, and they would look normal.  Two animals with the recessive albinism gene would look normal but could have an albino baby.  We saw that when looking at genetic crosses, we name a gene with a letter, and the capital letter is the dominant form while the lowercase letter is the recessive form.  Albino animals are called "aa" because albinism is recessive.  Animals that are "AA" or "Aa" are not albino, they have normal pigmentation.  In the game, we had to figure out how to breed a lemming baby that had albinism and also a long tail.  We could use Punnett squares to check for each pair of lemmings what the possible babies were and what the chances were for getting each baby.  Finally, we got a long-tailed albino baby lemming.  Then they all jumped off a cliff!