animal genetics: dominant vs. recessive traits
DESCRIPTION
Animal Genetics: Dominant vs. Recessive Traits. Intro to Agriculture Science. GOALS:. Explain the difference between dominant and recessive genes. Use a Punnett Square to predict genotypic and phenotypic ratios of offspring. What do we already know?. review…. Phenotype. - PowerPoint PPT PresentationTRANSCRIPT
Animal Genetics:Animal Genetics:Dominant vs.
Recessive Traits
Intro to Agriculture Science
GOALS:GOALS:
Explain the difference between dominant and recessive genes.
Use a Punnett Square to predict genotypic and phenotypic ratios of offspring.
What do we What do we alreadyalready know? know?
review…
PhenotypePhenotype
Appearance! Result of Genotype
Example:
Bw = Black Coat
Because
B is dominant
GenotypeGenotype
The genetic makeup! Alleles from parentsWhat you can’t see
Example:
Alleles that code for good milk production.
AllelesAlleles
A pair of genesThat code for the same trait
Example:
Hair ColorEye Color
Height
What do we What do we need toneed to know?know?
vocabulary…
Dominant GenesDominant Genes
Determine what the offspring will look like!
Expressed as capital lettersMask recessive genes.
Example:B=Black w=White
Dominant Allele = B
Recessive GenesRecessive Genes
Sometimes determine what the offspring will look like.
Expressed as lowercase letters
Example:B=Black w=White
Recessive allele = w
What is it called What is it called when both when both allelesalleles are the are the
same?same?
Homozygous
ExampleExample
AA or aa
Identify... Dominant & Identify... Dominant & RecessiveRecessive
AA or aa
? ?
AA or aa
Homozygous
Dominant
Homozygous
Recessive
What is it called What is it called when both when both allelesalleles are are
different?different?
Heterozygous
ExampleExample
Aa
Lets Get to It!
GeneticGeneticCrossesCrosses
MonohybriMonohybrid Crossesd Crosses
Punnett Punnett SquaresSquaresGeneticGenetic
CrossesCrosses
Punnett Punnett SquaresSquares
MonohybriMonohybrid Crossesd Crosses
What the What the heckheck are they? are they?
Punnett squares are genetic crosses used by biologists to predict the probability that certain traits will be inherited by offspring.
What do they What do they looklook like? like?
Punnett Square:
MONOHYBRID CROSSMONOHYBRID CROSS
A Punnett Square
Using one pair of contrasting traits
Ex: hair color
Example #1:Example #1:
Homozygous vs. Homozygous
Example #1:Example #1:
A White Sow (ww)
crossed with
A Black Boar (BB)
B
B(BB)
w w
(ww)
Bw Bw
Bw Bw
Homozygous vs. Homozygous
Example #2:Example #2:
Homozygous vs. Heterozygous
Example #2:Example #2:
A White Sow (ww)
crossed with
A Black Boar (Bw)
B
w(Bw)
w w
(ww)
Bw Bw
ww ww
Homozygous vs. Heterozygous
Example #3:Example #3:
Heterozygous vs. Heterozygous
B
w(Bw)
B w
(Bw)
BB Bw
Bw ww
Heterozygous vs. Heterozygous
Result…Result…
Try it!Try it!
cfu…