the branch of biology that studies the transmission of hereditary
information from parents to offspring
GENETICS
http://www.siskiyous.edu/class/bio1/genetics/
http://www.siskiyous.edu/class/bio1/genetics/cross_pollination.html
http://www.newpathlearning.com/MML/HEREDITY/files/PeaLab.swf
T = tall
t = short
INCOMPLETE DOMINANCE
when one allele (form of a
gene) is partially dominant
over the other
 it is a blending of the alleles

ex. Four O'clock Flowers (key
below)
R = red
RW = pink
W = white
MORE PRACTICE PROBLEMS
4) Use a Punnett square to show the offspring of
a cross between a red Four O'clock flower and
one that is heterozygous. Give the phenotypes
and genotypes of the offspring.
5) Use a Punnett square to show the offspring of
a cross between a homozygous white Four
O'clock flower and one that is heterozygous
pink. Give the phenotypes and genotypes of the
offspring
CODOMINANCE
this time, both the alleles are expressed, but they
are not blended together
 in humans, this is like hair texture and blood
groups

ex. cattle coat color (key below)
R = red
RW = roan (where both red and white are
expressed)
W = white
MORE PRACTICE PROBLEMS
6) Use a Punnett square to show the offspring of
a cross between a homozygous white fur cattle
and one that is roan. Give the phenotypes and
genotypes of the offspring.
MULTIPLE ALLELES




when there are more than 2 alleles for a gene
in human blood types there 3 possible alleles for the ABO blood
typing system
IA = A antigen http://learn.genetics.utah.edu
/content/begin/traits/blood/
IB = B antigen
i = no antigen
both IA and IB are dominant over i but,
both IA and IB are codominant with each other (that means, they are
both expressed equally)