You cut a small circular piece of DNA with EcoRI and obtain two fragments of 6 and 4 kb on an agarose gel. You cut the same piece with BamHI and obtain two fragments of 9 and 1 kb. When you perform a double digest, you obtain only 3 fragments (5, 3, and 1 kb). What is the most likely explanation

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

i think it is dna, i'm not totally sure but i think it might be.