2018/09/04

Identical DNA, similar outcome? Forget it.

Cloning won’t resurrect your pet because DNA doesn't determine characteristics

https://viagenpets.com/coat-color-spot-pattern-cloned-animals-genetic-donor/

Excerpt: "There are some unique coat color variations in cats, particular calico cats. On December 22, 2001, a kitten named CC made history as the first cat—and the first domestic pet—ever to be cloned. But CC was a black and white tiger tabby and Rainbow was a calico. How is that possible?

“The answer lies in the X chromosome. In cats, a gene that helps determine coat color resides on this chromosome. Both CC and Rainbow, being females, have two X chromosomes. (Males have one X and one Y chromosome.) Since the two cats have the exact same X chromosomes, they have the same two coat color genes, one specifying black and the other specifying orange. Very early in her development, each of Rainbow’s cells “turned off” one entire X chromosome, thereby turning off either the black or the orange color gene. This process, called X-inactivation, happens normally in females, in order to prevent them from having twice as much X-chromosome activity as males.""


https://www.britannica.com/list/cc-the-first-cloned-cat

"Meet CC, short for Carbon Copy or Copy Cat (depending on who you ask). She was the world’s first cloned pet."

CC was genetically identical to Rainbow, the cat who donated the genetic material. But the cats looked different because coat patterns and other features can be determined in the womb.

Although CC was a clone of Rainbow, she grew up as her own unique self, with her own look and personality."

My comment: The information required for variation already exists in the cell. No mutations were needed for these cats to have different phenotypes. Reading of DNA is controlled by epigenetic factors and mechanisms. X-inactivation is regulated by certain histone epigenetic markers. Genetic mutations disrupt biological information leading to faulty genes, information degradation and diseases. DNA is just a passive information library controlled by the epigenome. More about this can be read from here:

https://blog.episona.com/epigenetics-explainer-guide/

Epigenetic Patterns Can Change Physical Characteristics at the Organismal Level

"For example, mice with methylation at the agouti gene are obese and yellow in color, while their unmethylated counterparts have normal weight and have brown coats. Note that these two mice are genetically identical and only differ epigenetically (i.e., different DNA methylation patterns).The coat color difference relates to the expression of different types of skin pigment.

DNA methylation is an epigenetic mechanism that can alter gene expression by binding to promoter regions and suppressing gene expression within specific genomic regions. It does this by blocking the ability of transcription factors (blue dots) from binding to the DNA and allowing transcription (the formation of RNA) from occurring."