1) Understand the genome equivalence theory and how this theory can be proved (and was) experimentally.

Question

UpStudy AI · Accepted Answer

The genome equivalence theory (also known as the nuclear equivalence or genomic totipotency hypothesis) states that every cell in an organism carries a complete copy of the genome and, in principle, has the potential to generate an entire organism. In other words, although cells become specialized through differentiation, they do not lose any genetic information; rather, they merely express different subsets of genes depending on their function.

The experimental proof of this theory came from several key experiments, most notably:

1. Early Embryonic Implantation Experiments (Briggs and King, 1952):
 • Briggs and King performed experiments on frog embryos by transplanting nuclei from early blastula cells into enucleated eggs (eggs from which the nucleus had been removed).  
 • Their results demonstrated that the transferred nuclei could direct normal development, indicating that these nuclei, even after a few rounds of cell division, retained the full complement of genetic information.

2. Nuclear Transplantation Experiments (John Gurdon, 1960s):
 • Later, John Gurdon extended these studies by using nuclei from more differentiated cells (for example, intestinal epithelial cells) of tadpoles.  
 • In his experiments, the nucleus from a differentiated cell was transplanted into an enucleated oocyte.  
 • The resulting embryos, although less efficient in development compared to those using nuclei from early embryonic cells, still developed into normal organisms.  
 • Gurdon’s work was critical because it showed that even differentiated cells retain the complete genome necessary for building an organism, albeit in a “silenced” form for many genes.

3. Cloning in Mammals (e.g., Dolly the Sheep, 1997):
 • The cloning of Dolly the sheep using somatic cell nuclear transfer further supported the theory.  
 • In this procedure, the nucleus from a differentiated adult mammary gland cell was inserted into an enucleated egg.  
 • Dolly developed into a full sheep, confirming that the nucleus from a specialized cell contained all the genetic information required to form an entire organism.
 • Although additional layers such as epigenetic reprogramming play roles in the efficiency of reactivating genes in such contexts, the success of these experiments underscores the genome equivalence principle.

In summary, the genome equivalence theory was experimentally proven by demonstrating that nuclei from both undifferentiated and differentiated cells can, when placed in the appropriate embryonic environment, direct the formation of a complete, functional organism. This collective body of evidence underpins our understanding that cell differentiation is regulated by selectively expressing certain sets of genes rather than by losing any part of the genetic material.
The genome equivalence theory states that every cell in an organism contains a complete set of genes and can potentially develop into a whole organism. This was proven experimentally through: 1. **Briggs and King's Experiment (1952)**: Transplanting nuclei from early frog embryos into enucleated eggs showed that these nuclei could direct normal development. 2. **Gurdon's Nuclear Transplantation (1960s)**: Transferring nuclei from differentiated cells into eggs resulted in normal tadpoles, indicating retained genetic information. 3. **Cloning of Dolly the Sheep (1997)**: Successfully cloning a sheep using a nucleus from a specialized cell confirmed that differentiated cells contain all necessary genetic information. These experiments demonstrate that cell differentiation doesn't involve losing genetic material but rather controlling gene expression.

1) Understand the genome equivalence theory and how this theory can be proved (and was) experimentally.

Upstudy AI Solution

Answer

Solution

The Deep Dive

Related Questions

Latest Biology Questions