The gene that determines coat color in calico cats can have

The gene that determines coat color in calico cats can have either black (B) or yellow (Y) allele and is located on the sex X chromosome. The \"tortoiseshell coat\" see pic below) arises due to randomness of X-inactivation in a female heterozygous for coat color (X^BX^Y) Can a male cat ever have tortoiseshell coat? Provide rationale to your answer.

Solution

THE SIMPLE LOGIC IS MALE HAVE ONLY ONE X CHROMOSOME WHERE AS FEMALE HAVE TWO X CHROMOSOMES. THE MALE EITHER HAVE THE X CHROMOSOME WITH BLACK OR YELLOW. AS THOSE ARE CO DOMINANT, THE TORTOISE SHELL COLOUR ONLY EXPRESSES IN THE PRESENCE OF TWO GENES HENCE TORTOISE SHELL IS NOT POSSIBLE IN THE MALES.

FOR EXPLNATION FIND THE BELOW PUNNET SQUARE

FEMALE X MALE

XbXy X Xb Y

GAMETES

MALE

FEMALE

Xb

Y

Xb

Xb Xb – female, black

Xb Y – male black

Xy

XY Xb – female, tortoise shell

Xy Y – male yellow

IF YOU NEED ANY FUTHER EXPLANATION COMMENT

GAMETES	MALE
FEMALE	Xb	Y
Xb	Xb Xb – female, black	Xb Y – male black
Xy	XY Xb – female, tortoise shell	Xy Y – male yellow