Today, with our 5th grade visitors, we learned about Pedigree charts. We used the Weasley's family tree to look at how the trait for red hair is passed down through their family.




It's a lot of work to actually draw people on a pedigree, so instead, scientists use symbols.




Above is the pedigree for Queen Victoria's family. It traces the trait for hemophilia. A disease where the blood does not clot.


Homework: Read and take notes on the information below. You will have a 4 question reading quiz on this information at the start of class. Three questions will be definitions and one question will ask you to THINK!

An excerpt from ExploringNature.org's explanation on genetics

Gregor Mendel, was a monk in Austria in the mid-1800s who raised peas in the monastery gardens. While breeding his peas, he made some big discoveries. They were discoveries about genetics.

The peas had several traits he could see. Some plants were tall and some were short. Some had wrinkled pods and some had smooth pods. Some pods were green and some where yellow. The flowers were white or purple. Mendel looked at each trait and learned how they were passed down to the offspring plants. Since plants breed using pollen, Mendel controlled which plants pollinated other plants. This was how he discovered many important genetic rules.

How an individual looks and what their genetic code is sometimes do not match up. This is the difference between genotype and phenotype. The genotype is the actual genetic make up of an individual. The phenotype is what that individual looks like.

Traits that show up more often are called dominant traits. Traits that show up less often are called recessive traits. If an individual with dominant traits breeds with an individual with recessive traits, this can result in a hybrid offspring. Hybrid individuals can look like they have dominant traits (phenotype), but actually be hybrid (genotype).

Hybrid plants are different from dominant plants even if they looked the same. Each gene has two chances at a trait – two copies — two alleles. So a hybrid plant could be carrying the allele for a recessive trait even if you can’t see it. So, for example, a hybrid plant might be tall like its dominant parent, but it still could have an allele for shortness that you don’t see. This is the difference between genotype and phenotype. The genotype is the actual genetic make up of an individual. The phenotype is what that individual looks like.

This can be illustrated with a simple chart. It’s called a Punnett’s Square.