CHANGING THE SEX CHROMOSOMES IN C. ELEGANS
I. Wild-typemale XO hermaphrodite XX
II. Using tra-1 mutations
tra-1(o)mutations [(o) signifies a loss of gene function] are recessive and turn the animals (whether XO or XX) into phenotypic males.
tra-1(d)mutations are dominant and turn XO or XX animals into females.
The tra-1 gene is on the third chromosome.
The cross tra-1(d)/tra-1(o)female X tra-1(o)/tra-1(o)male will produce the same male and female progeny.
If we rename the tra-1(d)-containing chromosome W and the tra-1(o)-containing chromosome Z, we see that we have a WZ/ZZ system.
III. Using an IV:X translocation
If an X chromosome is joined to a IV chromosome (X-ray can cause this), we get a translocation chromosome (IV:X).
Animals with one normal IV, no normal X, and one IV:X translocation are males.
Animals with two IV:X translocations are hermaphrodites.
If we rename the IV chromosome Y and the IV:X translocation X, we see that we have produced an XX/XY system.