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Randomness in Heredity

The game can help...

The desire to get the right robot to win the game focuses the player's attention on the random nature of robot heredity. The recycler in RoboRiot helps students to visualize and experiment with the notion of randomness. When they put a pair of robots in the recycler, they can see that there is a random selection of alleles from both sides. Randomness is in play, because you cannot be sure which allele will be contributed by each robot. Each try in the recycler produces an unpredictable outcome or pairing of alleles, and the outcome of each try does not affect future attempts.

Teaching Snapshot

The relationship between random inheritance and robust species populations

A teacher introduces the concept that, because traits are randomly inherited, genetic diversity is important for the stability of species populations. He uses the RoboRiot game to ground the discussion, noting that, because all of the recycler outcomes are random and cannot be chosen by the player, successful gameplay requires a player to have a variety of alleles, making more random outcomes possible. He refers to an experience that many students had during gameplay—they were better prepared to confront whatever type of robot came their way if they established a large and diverse robot team. The teacher explains, “When you selected a robot for an encounter, the ability to choose from a variety of robots helped you win. In the real world, the more alleles there are, the better the chances of survival. Different alleles must be present to be candidates for selection.”

Heredity Slideshow

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What the Textbooks Say

While most textbooks address the concept of meiosis, explaining that during this process pairs of chromosomes separate and that alleles for each trait also separate into different sex cells, little if any time is spent helping students understand that this is a random process. This idea of chance is sometimes addressed using a coin toss activity, but how chance relates to meiosis is not given much attention. The role of chance in the combining of sex cells is further complicated when students are introduced to Punnett Squares and learn that you can mathematically predict the traits of offspring, if you know the genetic makeup of the parents and the traits follow a simple dominant-recessive pattern of expression.

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