Pedigree help

[mensamedlem]

I need help to find the answer to the questions below this text:

1) How is the inheritance?

2) Which genotypes do the persons have?

Source: http://www.flickr.com/photos/43857317@N02/4035026508/

Can you help me?

[JackBean]

You mean, what kind of inheritence, right?
Anyway, it seems to be recessive (as son of yellow isgreen, but his son is yellow again)
from left to right and from top down
aa ... AA ... aA ... aA
aA ... aA ... aA ... aA or AA ... aa
aa

EDIT just did the scheme more clear, hopefully

[mensamedlem]

Yes I mean what kind of inheritence.

Could it not be both autosomal recessive and x-linked recessive?

[mensamedlem]

I have written this:

It is X-linked recessive.

As you can see, only males inherit the disease. This is because they only have one X chromosome so if they inherit the affected X chromosome then they are guaranteed to express the characteristic.

Females can inherit one affected X chromosome and one unaffected X chromosome and since the characteristic is recessive, it will not present itself in females. However, the females can pass the affected X onto their sons, who will exhibit the characteristic.

It is possible for the female to get two affected X chromosomes so she'll exhibit the characteristics but it is much more likely that a male will inherit one affected X chromosome than a female inheriting two.

[JackBean]

yeah, I was also thinking, that it could be X-linked, but there is one man, whose child is ill. But it's true, that the boy would get from his father the Y chromosome, actually. Unfortunatelly, I can't access the photo now, to recheck it.

[mensamedlem]

http://www.flickr.com/photos/43857317@N02/4035026508/

[JackBean]

Well, yeah, I think both could work in this case