Introduction to Genetics!

By Saydee Deal

Heredity: Crash Course Biology #9

Whats the difference between Genotypes and Phenotypes?

Genotypes are the expression of a particular trait, in other words, the letters ex) hh or Hh

Phenotypes are a set of alleles that determine the expression of a particular characteristic, or the traits. ex) Having blonde hair or having brown eyes

What's the Difference in Homozygous and Heterozygous?

HETEROZYGOUS has 2 alleles for a trait and one is different. ex) Hh or Tt

HOMOZYGOUS has 2 alleles for a trait and both are the same. ex) GG or vv

Dominant vs. Recessive

Dominant is the allele that masks or hides the recessive trait.

Recessive is the allele that masks or hides BEHIND the dominant trait.

How can someone predict the traits of offspring?

PUNNETT SQUARES can predict traits of an offspring. You have a box with 4 squares. Put your fathers genotypes on top and the mothers genotypes on the side. Take on genotype from your mom and your dad and match them in the box. Then you can predict your phenotypes based on the outcomes.

Why is it important to study the principles of inheritance (how traits are passed on to offspring)?

It is important to study the principles in order to understand how we have certain traits. Without knowing this, we wouldn't be able to understand or predict our phenotypes. We can thank Gregor Mendel for his amazing discovery that led to this amazing lesson.