In a family of six children, where both parents are heterozygous for albinism, what is the probability that four are normal and two are albinos?

Okay. So this question takes that, the problems that we've been doing before a little bit further. And it says, in a family of 6 children, so we're gonna have to do the Pascal's Triangle again to figure out what that 6 line is. But in a family of 6 children, where both parents are heterozygous for albinism, what's the probability that 4 are normal and 2 are albinos? So the previous question, we were working with males and females. So that was just one half. Right? Because anytime anyone has a child, there's a one half chance it'll be a male, and a one half chance it'll be a female. But this time, we're not asking male and female. So it's not necessarily gonna be 1 half. What we're asking for is for our norm normal and albino. So what's the probability that one child will be albino and what's the probability that one child will be normal? So in order to do that, in order to figure out that probability, we have to perform what? Our favorite tool in genetics. Right? A Punnett Square. So we say that there are that both parents are heterozygous for albinism. So, we have to use the Punnett Square to figure out what the probability of each of these cases are. So, if we do a Punnett Square, we realize that there's a 3 fourth chance is going to be normal. So we're going to set that as a and a 1 fourth chance of being albino, which we'll set as b. So, already, we're starting out with different numbers than we used before. Now, the second piece of information we need is the Pascal's Triangle. So let me go back. So remember, how do we start this triangle, if we're not given it? With our 3 ones. And then, we just add them together and we keep adding them together until we get the line that, we need. That was the line for 5. Let me do this. So 0, 1, 2, 3, 4, 5. We're dealing with 6 children, so we need this line here. It's going to be 1, 5 plus 1 is 6, 15, 20, 15, 6, 1. Remember, you get these by adding until you get the line that you need. So this is the line that we're interested in. So if we were to write out all the coefficients, I think that's right. Yeah. Throw them all out. So the first one would be the probability that all of the children are normal. Remember a is normal? This would be the probability that 5 of the children are normal and 1 is albino. This is the probability that 4 of the children are normal and 2 are albino, albino, which is exactly what the question is asking for. 4 are normal, 2 are albino. So if we write this question out, we do 15 times a, remember is 3 fourths, someone's wrote it wrong too, to the 4th. B is 1 to the 4th raised to the second. And so what does this equal? Well, this equals the probability, so let's figure it out. So we do 0.75 or 3 4ths raised to the 4th. We times that by, 0.25 or 1 4th raised to the second. And we multiply that by 15. And so that gets you which of these numbers? Give me a second to type it into your calculator if you haven't had a chance to do it yet. But the answer here is, c, 0.30 or 30 percent. So if you are heterozygous for, albinism and you have 6 children, there's a 30% chance that 4 will be normal and 2 will be albinos. So hopefully, you've started figuring out how to write this Pascal's Triangle, how to use the coefficients and the formulas to calculate these probabilities, because it will be useful. You'll likely see something similar to these questions, either in a quiz or test or, something. So, know how to do this. So, with that, let's now move on.

In a family of six children, where both parents are heterozygous ...

1. Introduction to Genetics51m

2. Mendel's Laws of Inheritance3h 37m

3. Extensions to Mendelian Inheritance2h 41m

4. Genetic Mapping and Linkage2h 28m

5. Genetics of Bacteria and Viruses1h 21m

6. Chromosomal Variation1h 48m

7. DNA and Chromosome Structure56m

8. DNA Replication1h 10m

9. Mitosis and Meiosis1h 34m

10. Transcription1h 0m

11. Translation58m

12. Gene Regulation in Prokaryotes1h 19m

13. Gene Regulation in Eukaryotes44m

14. Genetic Control of Development44m

15. Genomes and Genomics1h 50m

16. Transposable Elements47m

17. Mutation, Repair, and Recombination1h 6m

18. Molecular Genetic Tools19m

19. Cancer Genetics29m

20. Quantitative Genetics1h 26m

21. Population Genetics50m

22. Evolutionary Genetics29m

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In a family of six children, where both parents are heterozygous for albinism, what is the probability that four are normal and two are albinos?