Mannie is not a pedigree, he is a cross breed (but as said all the symptoms of a true Manx)
MCAW, because the Manx gene is dominant, a cat only needs one copy of the gene to have the full set of traits. So effectively he is as Manx as you can get.
Bless him, he seems to have fallen on his paws with you.
The Manx gene, M, is one of a group of dominant traits where a cat needs only one copy of the gene to take on the characteristics. (Cat genetics is sooooooo fascinating
) Two other well-known dominant genes, none of whom are as problematic as the Manx gene and where you only need a single copy for a given trait are as follows:
A (agouti): the most common of all. A cat who is A- (either AA or Aa) will always be tabby.
W (dominant white): Cats who are W- will always be white as W masks all other colours. However, a cat that is W- and only carries one copy of the gene can have kittens of the colour(s) that the W gene is masking.
However, the majority of genes that provide the variations between the different breeds and also the different colours within the breeds are recessive, so both parents need to be carriers of the genes. Take blue cats as an example, to get blue kittens, either:
a) Both parents must be homozygous for blue (genes aa-dd) i.e. they are blue themselves
b) One parent must be blue (aa-dd) and one must carry blue (aa-Dd)
c) Or both must be aa-Dd i.e. both are black.