Genetics and Heredity

GENETICS

Some traits include:

People in a family may have things
in common. They can share traits.

You can inherit traits from your

parents.

Eye Color

Hair color

Skin Color

Body Shape

What is
GENETICS?

The study of how
traits are inherited

through the

interactions of genes.

Inheritance or Heredity

The passing of traits from parent to offspring

OFFSPRING

Another name for the
children of a male and
female parent.

What is a GENE?

▣
The material that
controls which
traits are
expressed in an
organism

▣
Genes come in
pairs and
offspring inherit
one copy of each
gene from each
parent

HALF OF YOUR GENES
COME FROM YOUR
MOTHER, HALF COME
FROM YOUR FATHER

Inside each nucleus of a cell are thread-like structures

known as ____________________. Chromosomes come

in ____________. Individuals usually have _________

copies of each chromosome, one from each parent.

pairs

two

HOW ARE TRAITS DETERMINED?

chromosomes

HOW ARE TRAITS DETERMINED?

_________, also known as the

molecule of life, is found within

chromosomes. A __________ is a

short segment of DNA. Genes

contain instructions that

make ____________, which

determine ___________.

DNA

gene

proteins

traits

Multiple Choice

Where is your DNA found?

• Only in special cells in our body.

• In every cell in our body

• In the cytoplasm of our cells

Multiple Choice

How many chromosomes do we have?

• 23

• 12

• 32

• 104

What if they Reproduced?

What if they Reproduced?

Think Pair Share

1. What did you notice?

2. What did these examples tell you

about how offspring get their
traits?

Individuals inherit ________ forms of each

__________, one from each parent. The

different variations of a gene are known as

___________. Alleles are represented with

lowercase and uppercase ____________.

two

gene

alleles

letters

To show the different forms of a gene, color each set of

alleles on the chromosome a different color.

DOMINANT GENES

● ____________ expressed when present

● Shown as ____________ letters

● Example:

Always

= DOMINANT

capital

Multiple Choice

Why do we see Alleles as pairs?

• That is just how it is done

• Scientist have only found two so far

• We get one from each parent

RECESSIVE GENES

● Expressed if ______ copies are present

● Shown as ____________ letters

● Example:

two

=recessive

lowercase

ALLELE

Alleles are different combinations of a gene

Allele Pairs

BB

Homozygous

bb

Homozygous

Bb

Heterozygous

The genotype is the ____________ makeup

of an individual. In other words, it is the pair

of _____________ an individual inherits from

their parents.

GENOTYPES

genetic

alleles

Note: Always write the dominant (capital)

letters first when writing genotypes

EXAMPlE GENOTYPES

The phenotype is the observable ___________

or characteristics determined by the

genotype. For example, ______________

is a phenotype.

PHENOTYPES

traits

eye color

EYE COLOR

EXAMPlE PHENOTYPES

Multiple Choice

Which one is a phenotype?

• Bb

• AA

• cc

• tall