00:01
The mini pedigree below illustrates a pair of expectant parents.
00:05
So the one with shaded is affected by a fully penetrated autosomal trait.
00:11
So this person is also heterozygous.
00:15
The other is unaffected and lacks the dominant allele.
00:19
So you can see that the male is affected and the female is not affected.
00:24
And the unborn child of this couple is represented by the diamond, but the phenotype is a nun.
00:31
Now we know there is an snp locus 10 map unit from the gene determining the trait.
00:36
So the snp has three different alleles, a, g, and c.
00:46
And the genotype of this individual for the snp is shown by the pedigree symbol.
00:51
So you can see that the heterozygous parent is a, g, and the non -affected female is c, c.
00:57
And the unborn child has a genotype of a, c.
01:02
So if the g allele of the snp is on the same chromosome as the dominant trait allele in the affected parent, what is the probability that the child will eventually express the trait? so in this case, you can see that we use snp to represent the dominant allele.
01:22
So let's say the dominant allele, let's say, is called capital d and the recessive is lower d.
01:34
So if we draw the two chromosomes, you can see that you have this dominant trait.
01:44
If you have a d here and then you will have a g here.
01:48
So these two, this is the g is the snp is 10 -map unit in between.
01:57
And it's on the same chromosome as a d, capital d, the dominant allele.
02:02
Now, this also tells us that a and c associate with the recessive, lower d.
02:10
So if you have a lower d here, then you will either have an a or a c here.
02:18
Now, if you look at our case, you can see that the heterozygous parents that was dominant phenotype has a, g, and the female has c, c.
02:31
So the child actually has a phenotype or genotype of a, c...