I have green eyes, so does my brother, mother, father and grandparents. First of all, is this rare? and second of all, how do green eyes even come in to existence? I know that brown is the most dominant allele, followed up by blue, and I've heard that green is somewhere in the middle, and it also depends on light reflecting off of them. Is green also an allele? I would just like some clarification please

IIRC eye color is determined by two (or more alleles). One allele either codes for brown or blue, the other green and blue. In that system, green is dominant over blue, but both are recessive to brown. In order to know to answer the question whether it is rare, one would need to know the alelle frequency in a given population. Theoretically, one could expect green eyes more often than blue eyes, as the latter has to be fully homozygous to confer that phenotype. However, there are other contributing factors that may determine allele frequency (including composition of the population).

Thank you very much!