Transcript Genetics EOC Remediation

Genetics EOC
Remediation
Some definitions to know
 Gregor
Mendel - the Father of Genetics
 Trait - a characteristic that can be passed
to offspring
 Genotype – the pair of genes that make up
a trait (one from mom, one from dad)
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Aa, AA, aa
 Phenotype
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– What the trait looks like
Black or brown fur color
Independent assortment means
that genes are separated during
meiosis, and each egg and sperm
is unique.
Punnett squares are used to
predict the genotype and
phenotype of the offspring
Punnet Squares and Ratios
A test cross is used to determine
the genotype of an unknown parent
Types of Dominance
 Complete
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One allele is dominant and one is recessive
B allele for black fur
b allele for brown fur
If the genotype is Bb, the fur would be black,
because black is dominant
Practice crosses
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Flower
Red is dominant
White is recessive
Cross a homozygous
dominant red flower
with a heterozygous
red flower.
What are the
genotypic and
phenotypic ratios?
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Seeds
Green is dominant
Yellow is recessive
Cross a homozygous
recessive yellow seed
with a homozygous
dominant green seed.
What are the
genotypic and
phenotypic ratios?
Types of Dominance
 Incomplete
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When neither allele is dominant and the
phenotype is intermediate or a blend of the
two alleles.
R is the allele for red flowers
R’ is the allele for white flowers
The genotype RR’ would produce pink flowers
Incomplete Dominance
 Long
water melon (LL) * Round
watermelon (L’L’)
 Do
the cross
 What is the genotypic ratio?
 What is the phenotypic ratio?
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Remember – The phenotype in this case has
3 possibilities, LL long : L’L’ round: LL’ oval
Types of Dominance
 Codominance
When both alleles are dominant and each
allele is expressed in the trait
Type AB blood has both A and B antigens on it
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Punnet Square For Blood Types
IA
i
i
IB
Multiple alleles vs. polygenic
inheritance
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Multiple alleles
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more than 2 forms of
a gene
Bloodtype alleles
• IA
• IB
• i
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Polygenic inheritance
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When two or more
genes work together to
give you one trait
Ex. Hair and eye color
Sex linked genes are on the sex
chromosomes
(colorblindness and hemophilia)
XX = normal female
 XY = normal male
XhX = carrrier female
 XhY = hemophiliac male
XhXh = hemophiliac
female
 Males only have I X
A female who is a carrier
chromosome.
does not have that
 They cannot be carriers.
trait! She is not sick at
 This is why sex linked
all. She won’t even
disorders are more
know that she carries
common in men
that gene.
Pedigrees show the inheritance of
traits through families
Hemophilia – Offspring of Queen
Victoria
Chromosome map shows all the
genes on single chromosome
Karyotypes show the complete set
of chromosomes that a human has
Biotechnology
 Gel
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electrophoresis
Used in DNA fingerprinting to match DNA at a
crime scene with a suspect.