If I'm correctly understanding the question . . .
Few will manifest it in breeds that DQ a dewlap, as less of thoseanimals would be used for breeding as opposed to breeds where it is nota DQ. Therefore, the chance of inheriting the tendency of adewlap is higher in certain breeds.
Smaller breeds exhibit less of a dewlap do the larger ones although wehave a grand champion Holland Lop doe with 12 legs that suddenlydeveloped a huge, pendulous dewlap (a large dewlap is a fault inHollands).
In the wild, a large dewlap is not a common physical trait.Darwin had made some observations on the dewlaps of selectively bredlops, many of which exhibited large dewlaps and had made the notationin his writings that the "dewlap was not strictly inherited"(indicating that the development of a dewlap is multifactoral).
What I've found interesting is the fact that Darwin noted the largestdewlaps in the English Lops -- a breed known for malformations of thebreast bone such as "funnel" and "pigeon" breast. A geneticform of Cutis laxa (loose skin)is associated with thosedeformities. Loose stools is another health problemassociated with this connective tissue disorder. There aremany different forms of Cutis laxa (including lethal forms) that can beinherited ina number ofdifferent ways. Ibelieve a form of this defective gene plays a role in the developmentof a dewlap as well as other factors including being overweight.
Dr. Cramer, plastic surgeon from WI . . .
Q. Why do some people get a "turkey gobbler" neck?
"A. Genetics! Unfortunately, some inherit a genetic tendencyfor excessive looseness of the neck skin combined with excessive fat inthe neck. This is very difficult since diet and exercise willnot change the genetic cards that were dealt."
Male pattern baldness is an inherited X-linkedgene. It can occur in females, just less often as it isinherited in a way that is recessive in females and acts as a dominantin males.
QUOTE: Actually the fact that male pattern baldness is a result of a gene
passed on from the mother has been known well before the big push for the
human genome project. Also, male pattern baldness is NOT a dominant
autosomal gene. In fact it is a recessive gene on the X chromosome (sex
chromosome). If you are a male you have one X chromosome and one Y
chromosome. Thus, for males, if you have one X chromosome and the recessive
gene on that X chromosome you will have pattern baldness (or whatever
recessive trait).
Females can have pattern baldness as well but they would need
recessive alleles (alternate form of a gene)on both of their X chromosomes
(again females are XX and males are XY,) this is why baldness in women is
rare. Females at least have that extra X to save them from a recessive
allele on the other chromosome.
If you remember each parent donates one sex chromosome to their
offspring. Thus if you are a male we KNOW the Y chromosome came from your
father (because in humans it is the sperm from the male that determins the
sex of the offspring - males make both X and Y carrying sperm)and the X
came from your mother. The allele for pattern baldness is carried on the X
chromosome that means you would inherit pattern baldness from your mother.
Michael S. Robeson II - geneticist
So . . . . my conclusion is that the dewlap is an inherited trait that serves no practical purpose. 
Pam
ps -- told youI was loooooooooong winded LOL
