Coin Sex Lab

In this lab, we learned how to use punnet squares to predict what our offspring will look like and what traits they will have. The coins served as genes and the two sides of the coins served as alleles. The flipping of the coin modeled meiosis and putting them together modeled recombination, or in other words, sex. The coins also showed how probability of something happening can be different from what actually happens. We did multiple autosomal crosses, where the sex chromosomes are not involved, and one x-linked cross, which is when the sex chromosome are involved. We used two sets of a coin each to represent a monohybrid cross, and two sets of two coins each to represent a dihybrid cross. In a few of our tests we labeled both sides of the coin the same letter to represent a homozygous trait, but in others we labeled the two sides differently to represent a heterozygous trait. When we preformed the di-hybrid cross, we got results that were slightly different than what was expected. The punnet square gave us a phenotype ratio of:

9 Brown Hair, and Brown eyes : 3 Blond Hair, and Brown eyes : 3 Brown Hair, and blue eyes :

1 Blond Hair, and Blue eyes

Our experiment had slightly different results, and gave us the phenotypic ratio of:

8 Brown Hair, and Brown eyes : 4 Blond Hair, and Brown eyes : 2 Brown Hair, and blue eyes :

2 Blond Hair, and Blue eyes

The slight difference between the probability, and what actually happened is due to the fact that probability is not always what is going to happen. It is possible to cross two heterozygotes, and get two recessive alleles in all ten offspring just like you can flip a coin ten times and get heads every time. This lab demonstrated the limits of probability. Probability can give you odds on what can happen, but until the event occurs there is no guarantee it will happen. Relating back to the coin, the probability of getting heads two times in a row is a 25% chance, but until you flip the coin twice you can't know if you will get two heads.

This lab relates to me because if/when I have children, then I can use probability to predict what they might be like, but I have no way to know for sure what traits they will have, until they are born.what traits they might have gotten until they are actually born.