Congrats! You

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Congrats! Youre HavingA Baby!
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Objective 1

• Explore the various types of gene interactions
  which contribute to genetic diversity

The way an organism looks is result of the way in
which the alleles interact. The genotype
determines the phenotype.
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Simple Dominance is defined as when one allele
completely expresses a trait and does not allow
the other allele to express itself.
Albinism is a disorder in which a person cannot
make the pigment, melanin. A person who is aa
has albinism. The AA and the Aa genotype
produce normal skin pigment.
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Incomplete Dominance is when both the dominant
and the recessive cannot fully express the trait
Snapdragons are flowers. Note that the dominant
R allele will produce a red petal flower. When
it combines with a recessive r allele, notice
the petals are pink. The combination of R and r
do not Allow for complete red.
What is the phenotypic ratio for the F1
Generation?
What is the phenotypic ratio for F2
Generation Between the F1 pink and white flower?
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Codominance is defined as when two different
alleles fully express the trait
Roan Cattle have a lighter color almost pinkish
appearance. It is not because they Have red
hair. It is by the arrangement of red and white
hairs. This cow inherited The dominant R allele
for red and the recessive r for white hairs.
Sickle Cell Anemia is a genetic Disorder caused
by a point mutation. A person with this disorder
would have red blood cells that are sickle
shaped. Note the genotype is aa. Look at the
Genotype AA, describe the normal cells.
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Polygenic Inheritance is when many genes control
a trait. As in the diagram below, skin color is
controlled by (3) genes. Noticed the letters
A, B, and C. These letters represent the (3)
genes.
The more dominant alleles inherited, the darker
the skin.
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Geneticists try to predict the possible genotypes
and phenotypes of the next generation. Sometimes
they use a simple Punnett square or the
mathematics of probability. Below is a Punnett
square for a monohybrid cross for flower color.
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About the Lab

• Parents will be heterozygous for a given trait
• Simple Dominance coin headD tailR
• Codominance coin headD tailR
• Polygenic Inheritance coin headD tailR
• Sex Determination coin headX tailY
• Read the directions carefully
• Complete Data for your two babies

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Example of a Monohybrid Cross in Humans (both
parents heterzygotes)
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Objective 2

• Compare expected phenotypic ratio to the observed
  phenotypic ratio

Trait Dominant Individuals Recessive individuals Observed Phenotypic Ratio Expected Phenotypic Ratio

Expected ratio comes from the punnett
square. Observed ratio comes from sampling a
population
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Objective 3

• Calculate the expected genotypic and observed
  genotypic ratios for a monohybrid cross for
  several types of gene interactions.

In this part of the lab, you should realize that
it is only the phenotypic ratio that change when
the allele interaction no longer exhibits a
simple dominance interaction.