A unique trait of the Catahoula (and many of the other Cur breeds) is the naturally occurring bobtail.
Any dog born with anything less than a full-length tail is a natural bobtail and carries this gene.
The length of the bobtail is inherited as a “variable expression” and can range from
as short as 1/2” to a 3/4 length tail.
In the Catahoula breed this gene is inherited as dominant -
only one bobtail parent is required in order for bobtail pups to be whelped.
The bobtail gene is inherited as heterozygous.
Meaning that a bobtail dog has 1 bobtail gene and 1 longtail gene - 1 inherited from each parent.
The bobtail gene cannot be inherited as “homozygous” or “doubled up on”.
Meaning that a bobtail dog cannot carry two bobtail genes.
Therefore, when breeding two bobtail dogs together, there will still be both longtail and bobtail pups
in the resulting litter as each parent carries 1 bobtail and 1 longtail gene.
(This is the same inheritance mode found in 19 other breeds 7 carrying the C189G bobtail gene.)
The longtail gene is inherited as recessive.
Bobtail = 1 dominant bobtail gene + 1 recessive longtail gene
Longtail = 2 recessive longtail genes
A longtail dog from a bobtail parent will not produce any bobtail pups when bred to
another longtail dog.
If an offspring does not inherit a bobtail gene from a parent then the trait is forever lost
in that dog - it has inherited 2 longtail genes.
The bobtail gene cannot be passed on as a “recessive” gene.
In the rare case that someone has reported bobtail pups “appearing” in a litter from two
longtail parents,it has been found that one of the parents is actually a
3/4 length tail and does carry the bobtail gene.