You perform classic embryology experiments to study how cells differentiate in the new species. a. The polar lobe produced in the 1-cell zygote of Ilyanassa snookii is inherited by only one of the two cells in the 2-cell zygote. You wish to show that, as in other snails such as Ilynassa obsoleta, cleavage of the zygote produces two daughter cells that are no longer equivalent. Describe one experiment you could perform to demonstrate such lack of equivalence of the two cells in the zygote. Clearly state the expected outcome of your experiment in the answer you provide.
b. JoAnn Render produced a cell-fate map for Ilyanassa (Render, Dev. Bio. 1997) and observed that the intestine in Ilyanassa larvae is formed from micromeres ME1 and ME2 (ME= mesentoblast), i. e., from a group of small cells initially formed at the 8-cell stage. You suspect that in I. snookii, the intestine is formed by the same cells. Describe one experiment that would confirm your suspicion. Clearly state the expected outcome of your experiment in the answer you provide.
c. Two micromeres, called 1a and 1c, give rise to cells that form eyes in Ilyanassa (see Gilbert and Barresi, 11thEd). In 1998, Hyla Sweet showed that one of the other micromeres, 1b, is also capable of forming eyes (Sweet, Development, 1998). She believed that a macromere (one of the large cells at the 8-cell stage) called 1D induces 1a and 1c to form eyes normally, but that 1b is normally too far away. Design one experiment to test this hypothesis. Clearly state the expected outcome of your experiment in the answer you provide.