The pedigree examples at the end (example #1 and #2) were not proofread by a geneticist. I made them quickly just to illustrate visually what rule #1 and rule #2 may look like on a real pedigree. Obviously the other sex offspring not included in the relevant rule might be affected, but for simplicity sake i made them non-affected in the examples. This is not intended to be used to learn the nuances of genetics, this is to get points right on test day. TL:DR - just memorize rule #1 and rule #2 if you want to get all X-linked pedigrees correct.
I have a pedigree where there is an affected father x wt female producing an affected daughter and unaffected son. But my professor stated all cases, autosomal dominant+recessive and x-linked dominant and recessive work here....but how cold I check for rule 2 here?
you made a mistake making the pedigree in the middle at minute 4:03 the sons should be dominant X and recessive X not both dominant. But other wise this is great. Thanks
Hi, is this only applies from 1st generation to second one usually? or it is also applicable from 2nd generation to third one and then from third to fourth?
She does, mother shows equal inheritance while the father by transferring Y chromosome to son and X one to her daughter shows unequal inheritance. That was just an example for you to determine the possible genotype of parents in a pedigree.
As a general pedigree structure/composition rule, aren't males always on the left and females are on the right in a couple that mates (ie:// example 1)
So if the allele is recessive and affected sons don't come from affected mothers, can we say based on that info that the disease is not X linked? Someone please help
