Silkie Chicken Genetics The Silkie Chicken Silkies originated

Silkie Chicken Genetics

The Silkie Chicken �Silkies originated in the Far East �Bantam Breed �Dark skin tone and 5 toes instead of the normal four �Are wonderful “brooders” and have been known to adopt baby geese/ducks if given the chance

Silkie Colors �Silkies come in a large variety of colors. �Black, Blue, and Splash are all on the same chromosome- we will deal with these colors in our study �Splash Hen (Ophelia)

�Blue Rooster (Nelson) �Splash Rooster (Cockatoo)

Black Hens (Peach & Petunia)

“Broody” Blue Hens

Other Colors �Other colors include buff, lavender, white, and partridge, but those colors are located on multiple chromosomes

Color Genetics �Black, Blue, and Splash are located on the same chromosome and are controlled by two different alleles. �We use the letters alleles “B” and “b” to represent the

Genetic Control of Color �BB = Black �bb = Splash �Bb = Blue �What do we call this? ? ? �Incomplete Dominance/ Blending Inheritance

Problem #1 �What color(s) of offspring would you predict from a cross between a splash silkie rooster and a blue silkie hen?

b b B Bb Bb b bb bb

Problem #2 �What color(s) offspring would you expect to get from a blue silkie rooster crossed with a blue silkie hen?

B b B BB Bb bb

Problem #3 �What color(s) offspring would you expect from a cross between a slash silkie rooster and a splash silkie hen?

b b b bb bb

Problem #4 �What color(s) offspring would you expect from a cross between a blue silkie rooster and a black silkie hen?

B B B BB b Bb BB Bb

Quiz 1. 2. 3. 4. 5. Is it possible for a black chick to be born from a splash rooster? What color(s) of parents could produce the splash phenotype? Can you tell the genotype of the heterozygous vs. the homozygous dominant silkie chicken? Explain. Show the Punnett Square for a cross between a blue rooster and a splash hen. List the % of the genotypes and phenotypes that would result from that cross.

Calculating Probability �To calculate probability, we have to determine all of the potential crosses that are possible 1. Blue Rooster x Blue Hen 2. Blue Rooster x Black Hen 3. Blue Rooster x Splash Hen 4. Splash Rooster x Blue Hen 5. Splash Rooster x Black Hen 6. Splash Rooster x Splash Hen

Calculating Probability �Then we calculate the ratios of each color of offspring from each potential cross (Black: Blue: Splash) 1. Blue Rooster x Blue Hen = 1: 2: 1 2. Blue Rooster x Black Hen = 2: 2: 0 3. Blue Rooster x Splash Hen = 0: 2: 2 4. Splash Rooster x Blue Hen = 0: 2: 2 5. Splash Rooster x Black Hen = 0: 4: 0 6. Splash Rooster x Splash Hen = 0: 0: 4

Calculating Probability �Next, we add all of the ratios to calculate a final ratio of predicted chick coloring �Black : 1+2 =3 �Blue : 2+2+4 = 12 �Splash : 1+2+2+4 = 9 �Final Ratio = 3: 12: 9

Calculating Probability �Now we can calculate our predicted probabilities of each color based on our ratio � 3+12+9 = 24 �(3/24)*100 = 12. 5% Black �(12/24)*100 = 50% Blue �(9/24)*100 = 37. 5% Splash �Later, we will calculate our percent error to see how accurate these predictions were!