fire and mello studied the effect of rnas made from plasmids on gene expression in the nematode c. elegans. mex-3 rna is normally present at high levels in uninjected embryos. drag and drop the c. elegans embryos to show the results fire and mello would have expected given several different hypotheses.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands