Question

Explain the rationale of sequestering a germline. What is the main difference between germline specification in Drosophila and C. elegans?

Answer 1

Rationale of sequestering a germline -

Difference between germline specification in Drosophila and C. elegant -

In Drosophila germ cells are formed from a specialized , maternally provided cytoplasm( that harbour germ line specific RNAs and proteins) that is sequestered at the posterior pole of the oocyte during oogenesis. This germplasm assembly is regulated by microtubule directed RNA and protein transport. Primordial germ cell RNA ( pgcRNA) is present throughout the embryo and enriched in germplasm. At the syncytial blastoderm stage pgcRNA is degraded in somatic cells and protected from degradation in germ cells.

On the other hand, the germline of Caenorhabditis elegans derives from a single founder cell , the germline blastomere P4. P4 is the product of four assymetric cleavages that divide the zygote into distinct somatic and germline lineages. P4 inherits a specialized cytoplasm ( germplasm) containing maternally encoded proteins and RNAs.