Random Interesting Thing: Black-and-orange markings are usually X-linked. All-ginger tabbies are therefore most often male (XY). Cats with a mix of orange and black patches, with or without underlying stripes (Musli & Skuggan) are usually female (XX), except for the occasional rare XXY males. During foetal development, one X chromosome in each cell is turned off at random - either the one carrying "orange" or the one carrying "black". The size of the resulting colour-patches depends on which point it's turned off - if it's early in development (when the kitten is just a few cells) the patches are bigger than if it's later.
(This also makes it quite probable that Black Male Kitten, Orange Male Kitten and Tortoiseshell-Tabby Female Kitten are all full siblings :-)
eta: Or Black Female Kitten? Not sure. Black can be either...
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Random Interesting Thing: Black-and-orange markings are usually X-linked. All-ginger tabbies are therefore most often male (XY). Cats with a mix of orange and black patches, with or without underlying stripes (Musli & Skuggan) are usually female (XX), except for the occasional rare XXY males. During foetal development, one X chromosome in each cell is turned off at random - either the one carrying "orange" or the one carrying "black". The size of the resulting colour-patches depends on which point it's turned off - if it's early in development (when the kitten is just a few cells) the patches are bigger than if it's later.
(This also makes it quite probable that Black Male Kitten, Orange Male Kitten and Tortoiseshell-Tabby Female Kitten are all full siblings :-)
eta: Or Black Female Kitten? Not sure. Black can be either...