Download AIM: How do organisms inherit genetic information from their parents?

AIM: How do organisms inherit genetic
information from their parents?
4/16/13
DO NOW:
1. Pick up today’s quiz
HOMEWORK:
ILS Review Book
1. Read p. 23-25
2. Answer Questions #1-19
on p. 27-33 in your
review book.
DUE- Tomorrow
What are genes?
 Contains hereditary
information
 Composed of DNA
What determines your
traits?
 One or many pairs of
your genes.
Where do you inherit you
traits from?
 Mom & Dad
How does sexual
reproduction differ from
asexual reproduction?
 Sexual – Combination of
genes (traits) from
sperm & egg.
 Asexual – exact copy of
the genes (traits) from
the parent cell.
What is a dominant trait?
 A trait that hides (overshadows) the affect of
another
What is a recessive trait?
 A trait whose affect may be hidden by a dominant
trait.
How do geneticists indicate whether a trait is
dominant or recessive?
 Dominant = Capital Letter “G”
 Recessive = Lowercase letter “g”
How do geneticists represent the
genes for a particular trait?
 Genotype: GG, Gg, gg
 One gene from mom & one
from dad
How do homozygous genes differ
from heterozygous genes?
 Homozygous = Pure (GG, gg)
 Heterozygous = Hybrid (Gg)
What is phenotype?
 The observable trait as a result
of the gene combination
What are the phenotype of the
following?
G= Green pods
g= Yellow pods
GG =
Green pods
Gg =
Green pods
gg=
Yellow pods
How can we predict the
probability of a trait
being expressed?
 Punnett squares
 Pedigree charts
According to the punnett
square at left, what is the
probability of Green
Pods? Yellow Pods?
 Green = 3/4 or 75%
 Yellow = 1/4 or 25%
A Punnett square is shown
at right. The dominant
trait is represented by R.
The recessive trait is
represented by r.
What percentage of the
offspring will most likely
show the dominant trait?
75% Dominant
25% Recessive
What is the probability of offspring with the
tongue roller trait? Mom = Rr Dad= rr
Mom = Rr
Dad = Rr
How are males represented in a pedigree chart?
 Males = Squares
How are females represented in a pedigree chart?
 Females = circles
How can you determine the offspring from a couple?