His mother was a yellow bitch!
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His mother was a yellow bitch!
My black trifactored male has sired four litters.......
All to yellow females.
Seven yellow three black
Seven yellow four black
Six yellow, one chocolate two black
Six yellow four black.....
I had an interesting litter last year. Black male (yellow factored) breed to a yellow female produced 5 yellow and 5 black puppies. The interesting part was that the yellows were are males and the blacks were all females.
This.
What most people do not understand is that the estimates using punnett squares (and lab color is not a typical Punnett square) are for each pup, not the entire litter.
It is exactly like lottery tickets, no matter how many you buy each ticket has the same odds as the others. Lets say a specific breeding combination has a 75% chance of being black and a 25% chance of being yellow. Each dog from that breeding has a 75% chance of being black and that is different then saying 75% of the litter will be black and 25% will be yellow. Over time and with a lage enough sample size you would see something close to a 75/25 mix, but not necessarily per litter.
Lastly, chromosomal segregation in conception is a crapshoot and completely random. Punnett squares are just mathematic estimates.
Hmm not a statt-i-tion, but flip a quarter 5 times get heads, even though it's 50-50 every-time seems like tails becomes more likely to come up unless somethings wrong with the quarter.
You can predict the probability of getting say 5 Heads in a row or 5 Tails in a row, even though the probability of an H or T on a flip is independent from the binomial. Here's an example...I hope I did make any boboos...
Flip a coin, 50% chance of H, 50% chance of tails (assuming fair coin).
Flip the coin 2 times, possible outcomes:
HH, probability of (.5)(.5)=.25
TT, probability of (.5)(.5)=.25
HT, probability of (.5)(.5)=.25
TH, probability of (.5)(.5)=.25
By analogy, if it is a litter of 2 puppies with 50% chance of black vs. yellow, 25% of the time you will get all yellows; 25% of the time it is all black; 50% of the time it is 1 yellow, 1 black.
Say you flip the coin 3 times, possible outcomes:
HHH, probability (.5)(.5)(.5)=.125/ all yellows
HHT, (.5)(.5)(.5)=.125 /2 Y, 1 B
HTT, (.5)(.5)(.5)=.125 /1 Y, 2 B
HTH, (.5)(.5)(.5)=.125 /2 Y, 1 B
HHT, (.5)(.5)(.5)=.125/ 2 Y, 1 B
TTT, (.5)(.5)(.5)=.125 /all blacks
TTH, (.5)(.5)(.5)=.125 / 2 B, 1 Y
THT, (.5)(.5)(.5)=.125 / 2 B, 1 Y
THH, (.5)(.5)(.5)=.125 / 1 B, 2 Y
So 12.5% chance litter of 3 pups is all yellow; 12.5% chance all black; 37.5% chance 2 Yellow one black; 37.5% chance 2 blacks one yellow.
Mitty,
Very well said and correct explanation. Statistics confuse a lot of people because they think history has an effect on the next coin flip. Same 50/50 chance holds true for each individual puppy, regardless if you are, talking about sex, eic, or cnm status.
Another way to ask the question would be, how many puppies would need to be born to be 90% sure you would observe one homozygous bb from a Bb x Bb.
I believe the number is 6. It depends on the distribution you are using to make your assumptions. You can google up Fischer's exact test to find more about this stuff.