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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.
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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)
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 “B” and “b” to represent the alleles
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 50% Blue, 50% Splash
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 b Bb bb 25% Black 50% Blue 25% Splash
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 b bb bb 100% Splash!!!
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 Bb B BB Bb 50% Black 50% Blue
Quiz • 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 • Blue Rooster x Blue Hen • Blue Rooster x Black Hen • Blue Rooster x Splash Hen • Splash Rooster x Blue Hen • Splash Rooster x Black Hen • Splash Rooster x Splash Hen
Calculating Probability • Then we calculate the ratios of each color of offspring from each potential cross (Black: Blue: Splash) • Blue Rooster x Blue Hen = 1:2:1 • Blue Rooster x Black Hen = 2:2:0 • Blue Rooster x Splash Hen = 0: 2: 2 • Splash Rooster x Blue Hen = 0: 2: 2 • Splash Rooster x Black Hen = 0: 4: 0 • 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+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!