Understanding the pedigree for MALE dogs

[jocoyn]

Ok - so if I am buying a male - honestly the ONLY thing he gets from his sire is the "Y" chromosome right? So all that matters THERE is the male tail line back to whichever family with slow gradual mutation over time.

So even if the sire was STELLAR would it really make much difference compared to another sire with a similar tail line (for a male puppy)? There are really only so many lines that run back to so many foundation GSDs.

The x chromosome coming from the dam can be either one from her own dam -OR- from her own sires dam and on back. It is 50/50 with what she HAS but you don't exactly KNOW which X chromosomes she has other than one she got from her sire (and you don't know which one HE got) and one she got from her own dam.

So....how do you know what characteristics she is carrying? I guess that is where the individual dog plays in and maybe some guessing based on obvious genetic traits?

Plus the female does the work of raising the pups inside and out and is much more critical, which is why I hear so much talk about strong motherlines. But the combination of genes .... so you would want a motherline where all females are strong dogs in their own right. Right?

The whole thing is downright intriguing and I can see where breeding only on the pedigree can become a fiasco......................

Am I 'getting this'? Who boy.

[Elaine]

I'm not sure if I'm understanding what you are saying, but a male dog gets half of all his chromosomes from his sire in addition to the y. I guess I don't get why you are only interested in the x & y chroms when there are so many other ones.

[jocoyn]

ok - brain fart - all those other ones - yes stet - I am not stupid just tired you are right.

[Ace952]

Jocoyn...you are on the right path. Chromosomes are important in trying to figure out what traits are passed onto the progeny. To do this you need to know the dogs in the pedigree (inside & out). You have to know the good and bad about the dog.
You just can't look at only the males though. You HAVE to look at the females.

I think this is a example of what you are talking about.



The most common type of sex-linked inheritance involves genes on the X chromosome which behave more or less as recessives. Females, having two X chromosomes, have a good chance of having the normal gene on one of the two. Males, however, have only one copy of the X chromosome - and the Y chromosome does not carry many of the same genes as the X, so there is no normal gene to counter the defective X.
An example of this type of inheritance is color blindness in human beings. Using lower case letters for affecteds, we have

• Affected male: xY Color blind
• Non-affected males XY Normal color vision
• Affected female xx Color blind
• Carrier female xX Normal color vision
• Clear female XX. Normal color vision

Now the possible matings:

xY to xx (both parents affected) xx females and xY males, all offspring affected.

xY to Xx (affected father, carrier mother) half the females will be xX and carriers, half will be xx and affected. Half the males will be XY and clear, half will be xY and affected.

xY to XX (affected father, clear mother) all male ofspring XY clear, all daughters Xx carriers.

Note that the daughters of an affected male are obligate carriers or affected. The unaffected sons of an affected male cannot carry the problem.

XY to xx (father clear, mother affected) xY males (affected) and xX daughters (carriers.)

XY to Xx (father clear, mother carrier) half the males affected (xY) and half clear (XY); half females clear (XX) and half carriers (Xx)

XY to XX (father and mother both genetic clears) all offspring clear.

Note that all female offspring of affected males are obligate carriers (if not affected.) Likewise, any female who has an affected son is a carrier. Non-affected sons of affected fathers are genetically clear.

This type of inheritance may be complicated by the sublethal effect of some X-linked genes. Hemophilia A in many mammals (including dogs and people) is a severe bleeding disorder inherited just like the color-blindness above. Many affected individuals will die before breeding, but for those who are kept alive and bred for other outstanding traits, non-affected sons will not have or produce the disease. All daughters, however, will be carriers.

[jocoyn]

Yes I think I was forgetting though that dogs have 39 (?) pairs of chromosomes of which one is an X and one is Y ......... and much *is* carried on those chromosomes but much is carried on the other ones.

Because I have not had a course in genetics since 1976 HAH! Brushing off the brain gears feeling stupid.

[Ace952]

Jocoyn....lol. Take the example I gave above and replace blindness with.......high prey drive.

Something to think about.

[Emoore]

Originally Posted by Ace952

Jocoyn....lol. Take the example I gave above and replace blindness with.......high prey drive.

Something to think about.

Although I doubt something like prey drive is carried on a single gene.

[Ace952]

Originally Posted by Emoore

Although I doubt something like prey drive is carried on a single gene.

I would agree with that. I would certainly look at the progeny and see if super high prey drive was passed on and then see who got it more males or females or was it even.

Then look to see how it was with different litters as the mating would play the important role.