Genetics 101Welcome to everything you wanted to know about Genetics!

Genetics… is the study of genes, heredity, and

variation among living organisms. It is studied through biology.

Remember… Traits vary in a population…this is

the key to species survival!

Offspring resemble their parents and this is from the passing of genetic information.

Inheritance Passing genetic information from

one generation to the next. Offspring inherit alleles from their parents.

Gregor Mendel Conducted pioneering work with inheritance.

Most important work was done with pea plants…he studied the trait of flower color.

He realized that plants did not combine colors (i.e. purple + white did not give a pale lavender color, but the plant was either white or purple). Why?

The answer…genes!

Animal Cell Every living thing is made of cells. Cells have organelles and one organelle

is the nucleus (center part of a cell). Inside the nucleus is DNA. DNA = an inheritance messenger; a

huge molecule containing millions of atoms; DNA is coiled into chromosomes in the nucleus

Chromosomes = structures that carry the message of inheritance

Alleles allele = specific active location on a

chromosome

Genes Gene = two alleles on the paired

chromosome working together; a pair of alleles!

Big Ideas! 1. Nuclei contain chromosomes. 2. Chromosomes come in almost

identical pairs. 3. Chromosomes have specific active

locations called alleles. 4. The two alleles in identical locations

on paired chromosomes constitute a gene.

5. A gene (two alleles working together) controls a trait.

Genotype Genotype = combination of alleles

in an organism’s chromosomes

AA, Aa, or aa, are all genotypes.

Phenotype Phenotype = what trait is

expressed in an organism

It’s what they look like!

The traits that the genotype produce is the organism’s phenotype!

Dominant Dominant Alleles = more influential

alleles; represented by an uppercase letter

AA or Aa

Recessive Recessive Alleles = less influential

alleles; represented by a lowercase letter

Aa or aa

Examples: blonde or red hair, blue or green eyes

Reading Assignment! With another person at your table

group, you will: Partner read pages 46 through 55. Under each green heading, you will

write down 2-3 things you learned in your Science Notebook!

From Genotype to Phenotype! Decode the genotype to produce

the Larkey’s phenotype!