Scientists have sequenced the full genomes of 91 sperm from one man, the first complete sequencing of a human gamete cell. It demonstrates the vast genetic variation in one person, according to genetic researchers at Stanford.
The 40-year-old sperm donor has healthy kids and his semen sample was normal, and researchers had already sequenced his whole genome using other cells. They were able to compare that result with the 91 individual sperm cells they isolated from his sample. This allowed an interesting view of recombination — the genetic mixing that ensures a baby's DNA contains genetic material from all four of its grandparents.
Recombination causes genetic variation in babies because of how it mixes the parents' DNA. Human cells have 46 chromosomes — two copies of 23 chromosomes — and in reproductive cells, these are partitioned into one copy of each 23. When these gametes (sperm and egg cells) join, the resulting fertilized egg has each set. When this recombination occurs, pairs of chromosomes line up, as Stanford's news site explains it. Sometimes during the queuing process, portions of matching chromosomes mix. This is responsible for the genetic variation in the resulting offspring.
"The exact sites, frequency and degree of this genetic mixing process is unique for each sperm and egg cell, and we've never before been able to see it with this level of detail," said Stephen Quake, professor of bioengineering at Stanford and lead author of this new study.
The researchers found that individual sperm's genetic mixing varied greatly, and some spontaneous mutations were more severe. Two sperm were missing entire chromosomes, for instance, which was a result of this mixing process. This would make them unlikely to fertilize an egg. As such, this study could have implications for fertility research.
"The DNA is the raw material that ultimately defines a sperm's potential," said co-author Barry Behr, a professor of obstetrics and gynecology. "If we can learn more about this process, we can better understand human fertility."
The paper appears in the journal Cell.
“The DNA is the raw material that ultimately defines a sperm's potential,” said co-author Barry Behr, a professor of obstetrics and gynecology. “If we can learn more about this process, we can better understand human fertility.”
...and how the Gods made us and what other programing remains in our junk DNA programing?
How did the human\ape\monkey leap frog ahead of the natural ape\monkey and become so greatly intelligent, aware of its own existance, develope artistic\imaginative abilities and making of tools, shed its fur, ability to walk and run upright and awareness of enviroment around it with its ever creative ability to adapt to its enviroment?
This is some nice research. Have they ever sequenced a whole family's genome? Grandma, grandpa, mom, dad, kids and possibly the mailman?
btw, am I the only person completely feed up with the ancient astronaut theories spreading like gonorrhea on popsci?
I applaud your free speech to speak of being annoyed with ancient astronaut theories. I encourage alternate points of view and many commentators too. Now that you are feed up, what will you do? What will you do, lol.
Perhaps you could elaborate on your points of view, rather than just whinny? But of course, that does take the risk of somebody complaining they do not appreciate your comments and views; dare to take the risk. By the way, this subject of ancient astronauts, does it have anything to do with " Sequenced for the First Time: the Genome of Human Sperm "? I believe you have just entered yourself in the catagory of being a troll. Take care." ;)
Oh, and if you call me a troll, I could give a hoot!
Sperm in a healthy man were issued without a full set of chromosomes? This explains a lot about infertility, especially when those incomplete ones can end up being the lucky winner. Too bad you can't guarantee the egg will receive an optimized sperm except through shortcut fertility needles or divine intervention.