LJ3 has been posted on the “Learning Journals” page.

1. One new (or ‘improved’) concept

The concept of maternal effect genes directing early embryogenesis and the importance of asymmetrical distribution of transcription products for development of Drosophila.

Maternal effect genes are a set of genes derived only from the mother that are transcribed and afterwards distributed asymmetrically in the oocyte prior to fertilization. After fertilization, these transcription products are responsible for directing early embryogenesis.

2. Thinking about your new or ‘improved’ concept

I have known for some time now that a set of genes expressed by the mother were responsible for organizing the development of the early embryo of Drosophila.
Recently I have learned how the mRNAs derived from these genes are asymmetrical distributed and fixed at specific locations in the oocyte. This gives rise to varying concentrations of certain transcription factors when translated. The asymmetrical distribution of transcription factors promote and regulate gene expression of the needed genes throughout embryogenesis.
Prior to this knowledge, I was not able to appreciate the simplicity of how a few maternal effect genes could offset the very complex process of directing embryogenesis. This made me realize that I did not really grasp the concept before.

The process of preparing the oocyte for asymmetrical development of an embryo involves many different factors to establish the right environment. So does the complex patterns of gene regulation involved. The outcome of these maternal effect genes is the foundation to orchestrate embryogenesis through gene regulation and polar gradients of transcription factors required to express specific genes in daughter cells.
This foundation, to me, is more a concept than a simple fact since it requires a high level of understanding before you can appreciate the mechanisms involved in the process.
Understanding this concept is important to comprehend the basics of early embryogenesis and how morphology is established and determined early in development.