Today

• Inventory your own easily observable genetic traits.

• Record observations of the genetic traits in our classroom, create a data table and make a bar graph to show the most and least common traits in the group.

Add these definitions to your paper:

• A gene is: ______________________________

• An allele is: ____________________________

• Genetics is: ____________________________

• A trait is: ______________________________

• Heredity is: ____________________________

• Dominant means: _______________________

• Recessive means: _______________________

The set of information that controls a trait; a segment of DNA

The different forms of a gene

The scientific study of heredity

A characteristic that an organism can pass on to its offspring through its genes

The passing of traits from parents to offspring

An allele whose trait will always show up in the organism when the allele is present

An allele that is masked when a dominant allele is present

• A human karyotype has 46 chromosomes. (23 from each parent)

• Chromosomes inside a cell's nucleus contain all the information needed to make a new organism.

• Chromosomes are made of DNA.

• Genes are sections of a chromosome's DNA that code for different proteins and control different traits.

• Different versions of genes are called “alleles ”

• Genetics is the study of inheritance.

• One of the easiest ways to study inheritance is by looking at physical characteristics or traits.

• Traits are things we often hear about, such as:

– Do you have your father’s eyes?

– Your hair is just as curly as Aunt Jane's.

– You look a lot like your Mom when she was your age.

• Some traits are easy to observe – hair color, dimples, number of fingers, etc.

• Other traits we cannot see- like blood type.

• Heredity is the passing of traits from parent to child.

• An organisms traits are controlled by the alleles of their parents.

• The more common trait isn’t necessarily “BETTER” than the other trait, it is simply the trait that shows up more frequently.

• Sometimes the more rare trait is actually “BETTER”

• Sometimes neither trait is “BETTER”

• Some alleles are stronger than others.

• Dominant alleles is one whose trait always shows up in the organism even when another allele is present. (Stronger)

• Recessive alleles are hidden whenever a dominant allele is present. (Weaker)

• A recessive trait only shows up when both alleles are recessive.

• Title your data table “Observed Traits ”

• Make 5 columns (1 large and 4 small)

• Make 18 rows

OBSERVED TRAITSME CLASS

YES NO YES NO

• Fill in the Traits as we go.

• Only fill in YOUR answers now, we'll get class totals at the end.

Cheek Dimples