Question for the genetics buffs?? - Page 1

OK;  the bitch determines the number of puppies;  does the stud dog determine the sex of the puppies or is that the bitch??  I always thought it was 90% the bitch;  but my friend said, how can that be since the male carries the XY factor??  I can't find my book on genetics;  they are still packed from when we moved 4 years ago.  Thanks for your help??  Nan

HI Nan,

While its obvious a bitch's body will determine how many eggs (ova) are dropped in a cycle..it doesn not mean its totally up to her as to how many pups there will be. IF the sperm can not travel properly,  are weak or problematic, that too will deermine end number results.

As for the sex  the male does as all female ova carry X as male sperm X and Y and the greeting/arrival of what one Y or X  will determine the outcome= the gender.

You may even be able to do some searching now if you cant dig your books out but would like the diagram..sometimes the visuals have more impact.

Cheers
Debi
www.sherman-ranch.us

Without BOTH participating, neither would determine much on their own.  There are many points along the chain of events in the reproductive process, where the actual gender outcome can be skewed from what is generally a 50/50 result.  It's not all like BAM, and bob's your uncle.  The male, for whatever reason, might be producing more x-bearing or y-bearing sperm on a given day....  the female may have produced antibodies that single out and attack a specific gender bearing sperm before they can reach her waiting eggs...  Nothing in the world is so neat and simple, and that's probably a good thing.

HI Nans GSD,

The chromosomes here are just as with humans, females carry only X(XX) chromosomes and males carry X and Y (XY) chromosomes. As only the male carries the Y chromosome, it's the male who can determine the sex of the pup.

FEMALE CARRIES :   XX                                 MALE CARRIES: XY

Mitosis (splitting up) of cells can create :

                              XX    or XY

(one X from the female and one X from the male = XX; One X from the female and Y from the male = XY)


here are some pages that you might find interesting:

http://www.thekennelclub.org.uk/item/327

http://mandevillehigh.stpsb.org/teachersites/laura_decker/genetics.htm

Hope that helps!

I agree with most of this. The female will determine the MAXIMUM number of possible pups in the litter. The male only produces the Y (male) chromosome.

However, there are several factors which can INFLUENCE the litter. PH of the bitches reproductive tract (acid enviorment can produce more males). When in the ovulaton cycle did mating occur, and how frequently. Motility of the sperm, quality of sperm, how often is the male servicing females (is he breeding more than one at a time?)

Case in point. This was my horses, but results would be the same. I had been breeding for many years. Always had a roughly 50-50 crop of foals. I was troubled by the flies constantly biting the horses, so acting on the advice of an Amish man, I began administering a 'home remedy'. It consisted of adding garlic to a gallon of cider vinegar, and top dressing the feed. So I did try it for the whole fly season. The mares foaled as usual, I bred them back for the following year. Next year 100% colts (male)! Even the mare I had bred for 10 years had her first and only colt! Incidently, the 'Home remedy' didn't really seem to work all that good either.

Yes, thanks Tings Tails that does help to clarify somewhat.  Clear as mud. 

Ookay, as a former biology teacher here let me try to clarify.

We all have 2 complete sets of chromosomes in our body. Humans have a total of 46, or 23 pairs. This includes two sex chromosomes, which are either XX  (for a female) or XY (for a male).

When the sperm and egg are forming, they undergo what's called reduction division, or meosis. This produces cells that have only ONE set of chromosomes. This has to happen, because when the sperm and egg unite, you are then back to the original number, with half coming from the father and half from the mother. This is how it works in any animal or plant that reproduces sexually.

SInce all the female's egg cells contain only an X chromosome, the male does determine the sex, as he carries both X and Y sperm. As has been mentioned above, the female can play a small role in sex determination, as certain conditions inside her vagina and uterus may favor one type of sperm cell over the other. But basically, the chances of getting a boy or a girl puppy are about 50/50.

Hope that helps!

Yes it does help.  So my mistake. 

Meiosis---(current biology teacher here) produces eggs and sperm.  Eggs all have one X chromosome.    Sperm can have either an X chromosome or a Y chromosome.   If a sperm containing an X fertilizes the egg, you get XX (female).  If a sperm containing a Y fertilizes the egg, you get XY (male).   

That is correct, however, only the male can produce the Y chromosome that is why the male determines the sex of the puppies, how many girls or boys as he and only he carries both X & Y.  Yeah.  I think I've got it.  Thanks to all  Nan