Early embryology; how the sperm unloads its genome (Introduction)

by David Turell , Saturday, March 14, 2020, 01:12 (1716 days ago) @ David Turell

It requires a certain enzyme:

https://phys.org/news/2020-03-sperm-dad-genome-merge-mom.html

"Researchers at University of California San Diego School of Medicine have discovered that the enzyme SPRK1 leads the first step in untangling a sperm's genome, kicking out special packing proteins, which opens up the paternal DNA and allows for major reorganization—all in a matter of hours.

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"Sperm can be up to 20 times smaller than a normal cell in the body. And while sperm carry only half as much genetic material as a regular cell, it needs to be folded and packaged in a special way in order to fit. One way nature does this is by replacing histones—proteins around which DNA is wound, like beads on a necklace—with a different type of protein called protamines.

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"... back in 1999, shortly after Fu published a paper that first described the enzyme's role in RNA splicing, a research group in Greece noted similarities in the sequence of amino acid building blocks that make up SPRK1 substrates (the proteins upon which the enzyme acts) and protamine.

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"'And, surprisingly, everything we tried supported our hypothesis—SRPK1 leads a double life, swapping protamines for histones once sperm meets egg."

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"Fu, Gou and team next want to determine the signals that instruct sperm to synchronize with the maternal genome."

Comment: Only partial knowledge of this precise series of steps is known. It has to have been designed. Chance hunt and peck could not work as a design method to produce proper coordinated fertilization.