Return to David's theory of evolution PART 2-3 (Evolution)

by David Turell , Thursday, June 16, 2022, 18:53 (889 days ago) @ David Turell

From a previous entry:

How did sex pop up?
DAVID: this study of hermaphrodites really adds little. They have both sexes to begin with. That does not explain how the two sexes appeared from organisms that simply used binary fission. This is one of the biggest developmental gaps in which sex's origin is not known.

dhw: We don’t know any of the “origins”, including that of life itself. However, you suggested that sex may have originated before the Cambrian. And we've been told that fundamental elements of the brain and nervous system existed much earlier than the Cambrian. This suggests the continuity of evolution (which you favour for the sake of a continuous line between bacteria and humans), as opposed to separate creation without precursors (which you favour as evidence for your God’s existence).

It required chromatin to appear so sex chromosomes could exist:

http://www.sci-news.com/biology/eukaryotic-chromatin-evolution-10894.html

"Like wool around a spool, the extreme space challenge requires DNA to wrap around structural proteins called histones.

"This coiled genetic architecture, known as chromatin, protects DNA from damage and has a key role in gene regulation.

"Histones are present in both eukaryotes, living organisms that have specialized cellular machinery such as nuclei and microtubules, and archaea, another branch of the tree of life consisting of single-celled microbes that are prokaryotic, meaning they lack a nucleus.

***

"They found that prokaryotes lack the machinery necessary to modify histones, suggesting archaeal chromatin at the time could have played a basic structural role but did not regulate the genome.

"In contrast, they found ample evidence of proteins that read, write and erase histone modifications in early diverging eukaryotic lineages such as the malawimonad Gefionella okellyi, the ancyromonad Fabomonas tropica, or the discoban Naegleria gruberi, microbes that had not been sampled until now.

“'Our results underscore that the structural and regulatory roles of chromatin are as old as eukaryotes themselves,” Dr. Grau-Bové said.

“'These functions are essential for eukaryotic life — since chromatin first appeared, it’s never been lost again in any life form.”

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"Using the sequence data, the researchers reconstructed the repertoire of genes held by the last eukaryotic common ancestor, the cell that gave rise to all eukaryotes.

"This living organism had dozens of histone-modifying genes and lived between one and two billion years ago on Earth.

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“'Viruses and transposable elements are genome parasites that regularly attack DNA of single-celled organisms,” said Dr. Arnau Sebe-Pedrós, a researcher in the Centre for Genomic Regulation at the Barcelona Institute of Science and Technology.

“'This could have led to an evolutionary arms-race to protect the genome, resulting in the development of chromatin as a defensive mechanism in the cell that gave rise to all known eukaryotic life on Earth.”

“'Later on, these mechanisms were co-opted into elaborate gene regulation, as we observe in modern eukaryotes, particularly multicellular organisms.'”

Comment: as Darwinist scientists they have their guesses as to how chromatin appeared. It could be a virus attack or a designing God. At any rate we came from Archaea. And to have sexual reproduction major modifications in DNA structure had to happen. Sex allowed for multiple possible complex new variations to appear, while simple binary fission couldn't do that. Design or chance, I chose design.