SEX -- LINKED
INHERITANCE
1: Y -- LINKED WITHOUT ANY X -- LINKED ALLELE
2: X -- LINKED WITHOUT ANY Y -- LINKED ALLELE
3: INCOMPLETELY SEX-LINKED MEANING THAT
AN X-LINKED GENE IS AN ALLELE OF A Y--LINKED GENE.
OTHER FACTORS CAN CHANGE THE MALE / FEMALE RATIOS IN SOME STRAINS.
ENVIRONMENTAL FACTORS, CROSS OF TWO UNRELATED STRAINS, MUTATIONS OR CROSSOVERS, ETC.
