“Alright class, let’s do a genetic problem. If a blue eyed man has children with a homozygous dominant brown eyed woman what are the genotypic and phenotypic ratiossssszzzzzzzzzzzzzzzzzzzzzzzzz”
“If Mendel crosses a green wrinkled seed with a yellow smooth seed…. ” *THUMP* <—student head hitting desk.
I got sick of the same old genetic word problems that require zero thought process and are as about as entertaining as emptying the lint trap in a dryer. But do not fret, John Romano is here to give you the red pill and show you how deep the genetic word problem rabbit hole can go.
There is a multi billion dollar industry that I am deeply embedded in, and tap into all the time for teaching biology.
Yes, the money spent on breeding and buying snakes is a huge industry and it has become that way because of genetics. No snake has a greater range of genetic possibilities than the ball python, a “drawer” snake that takes up very little room and comes in a wide range of genetic possibilities.
Because of these wide ranges of possibilities the potential for various word problems is limitless. If we can barely get kids to eat peas what makes us think they give the slightest interest in growing them?
But plop a ball python on their desk and all of a sudden it’s Science City, population you! Not only are the fireworks of color and pattern a huge draw but the real wow factor is when I have the students look up the price lists for these animals. Then all of a sudden there is a real world application to the reasons for knowing genetics.
They could make money! Look I hate using money as incentive with students, but there is right, wrong, and reality, and unfortunately money as a driving force is a huge reality for students forced to make minimum wage or live off their parents.
The added bonus of using snakes is the first thing they need to do is research the animal’s reproductive habits. However if you are just looking for quick word problems you can tell them that female ball pythons reproduce once a year, lays anywhere from 2-10 eggs, which then take around 2 months to hatch, and the offspring take 2-3 years to reach sexual maturity.
So let me give you an example of one of my word problems. I am going to start with the uber basic model.
You decide to try your hand at breeding albino ball pythons. Albinism is a simple recessive trait. Your first step isto acquire the snakes. First, which sex do you want the albino to be?
Answer: Male, a male can breed multiple females in a year and spread the albino gene to unrelated animals where a female albino can only pass her genes on once a year.
You purchase a male albino and a female heterozygous (het) for albino. You breed these animals together and she lays 8 eggs, all of which hatch. What are the genotypic, and phenotypic ratios of the clutch? How many albinos should you produce?
Answer: Genotypic ratio = 1:1 Phenotypic ratio = 1:1 Number of albinos = 4
Now this is a super basic problem, once you add money to the problem it becomes a little more exciting. I like to keep these as real world as possible so I pull up a ball python pricelist on my computer which can be found at Kingsnake.com. Admittedly you can get lost in the jargon of ball python breeding, but stick with what you know at first.
So lets check out a moderate problem I would ask my class.
You desperately want to produce piebald ball pythons but like most of us, lack the $1000 to buy a nice looking piebald. Knowing piebald is a recessive trait and having $200 to spend you decide to purchase a pair of heterozygous for piebald ball pythons. Male hets generally cost $50 and the female hets are $100. You receive the animals and decide to breed them. The female lays 4 eggs, and in 2 months they hatch. How many piebalds should you produce?
Answer: 1 piebald ball pythons. Lucky you, it is a male!
How many hets should you produce?
How many homozygous dominant pythons should you produce?
This is where I usually start asking students what their opinion is on their next move and explain why they chose to do this. There is no right answer, some students are looking to make as much money as possible and some students are looking to expand their breeding empire and reinvest in more snakes. Allowing this type of open ended question lets the students take ownership of the material.
Some sample answers would be…
Make money: Sell the piebald and normal looking snakes and breed your original pair again.
Expand empire: Hold back the piebald and the original hets to produce more piebalds in the future. Sell the normal looking ones.
But lets face it, who would ever want to give up a nice looking piebald ball python?
If you are unfamiliar with the ball python world this can seem like a daunting task, however with what I just gave you and a few hours of internet research you can get enough information to make your own problems. But if you aren’t interested in doing the background research, ask your students to research the morphs and come up with their own problems. Nothing makes a student feel more empowered than when they get to educate their teacher on a subject.
I can tell you from experience when connecting students to the real world and exposing them to an industry that they can actually be a part of makes them own the knowledge.
However if you want to do more research check out: The Snake Keeper. I personally know this couple and they are the best ball python morph people in the business.
If you have a working knowledge of morphs you can go to the high stakes Ball Python Classified on Kingsnake.
In fact I believe in this so much that I would be more than happy to video chat via Skype or google chat. If you are interested in learning more about this contact me to set up a video chat.
paleoromano at gmail dot com or on twitter: @paleoromano