#embryology

[omegaverse-biologist]

I fucking passed histology and embryology, meaning I'm abandoning my hiatus and coming back to explain how the omegaverse could happen from a biological stand point. I will make fem preg my life mission for wlw deserves more representation. My new theory: fem alphas store their testicles in the lips, stay tuned for my nonsense

[zelfstandig]

Brain development and the Brain Vesicles

It is incredible how such a sophisticated organ as the brain develops from a much simpler configuration. The universe is amazing!

[scienceguy22]

The egg that isn't an egg (but might work anyway).

Colossal is at it again. This is a company that is famously known to try & bring back extinct species, none of which have been successful—not a mammoth, not a thylacine, not a dodo, not a moa, not anything. Not even close. I've been following this topic for quite a while now, & all I've been seeing are press releases, fundraising efforts, cell-line editing experiments, computational genome reconstructions, & theoretical models for surrogate species. They seem to have taken a step forward recently, if the claims can be verified. They claim to have successfully hatched chicks using 3D-printed artificial eggs with a silicone-based gas exchange membrane, allowing the chicks to breathe air through the membrane without the need for supplemental oxygen. If true, this would be an improvement because former artificial eggs needed supplemental oxygen for the developing chicks to breathe. The former artificial eggs often failed because embryos suffocate without a natural shell's microporosity. This membrane allows oxygen diffusion, CO₂ release & humidity regulation.

The claim is clearly an overstatement that they "created the first shell-less incubation system." The technology (if proven accurate) is essentially a modification of existing methods. So far, the results have not appeared in a peer-reviewed scientific paper. It sounds impressive, but then it would, because it's a press release. It is not a "fully artificial egg." More precisely, a more apt description might be an artificial eggshell. Basically, they transferred the contents of freshly laid chicken eggs into the artificial shells, then incubated them until some chicks hatched. Colossal eggs require extra calcium because a real shell supplies some of this essential mineral during development. Colossal would like to use this method to revive the extinct giant moa, a flightless bird from New Zealand that could stand more than 12 ft tall (3.6 m) & weigh 510 lb (230 kg). They became extinct after Polynesian settlers arrived in New Zealand. The birds had no evolutionary warning signs about the danger humans brought with them. They were hunted relentlessly; they were basically sitting ducks.

But making a moa-like bird would require far more than a large artificial egg. This is a fundamental flaw that assumes the egg came first. Biologically, the egg is the last step, not the first. You cannot start with the container when you have no embryo, no yolk, no genome, no surrogate, & no developmental pathway. Scientists would first need to reconstruct ancient moa DNA from the bones they have. Then they need to edit 1,000s of genetic differences into the genome of a living relative, the emu, for example. Even then, it would be an engineered proxy/hybrid (a living bird designed to resemble an extinct one). Size is yet another problem. An egg yolk is a single cell, & it can't be enlarged like a balloon without collapsing developmental biology. You cannot print a yolk.

The strongest case for their technology may be to help rescue embryos from damaged eggs & support breeding programs for rare birds, for endangered bird conservation & controlled generation of genome-edited avian lines, rather than de-extinction itself.

[superiorart]

 ICSI vs. IVF: Understanding the Difference

ICSI vs. Standard IVF: Which Pathway Leads to Your Parenthood? When exploring assisted reproductive technology (ART), patients are often presented with a confusing alphabet soup of medical terms. The two most common procedures you will hear about are IVF (In Vitro Fertilization) and ICSI (Intracytoplasmic Sperm Injection). Understanding the difference is crucial for maximizing your chances of a…

 ICSI vs. IVF: Understanding the Difference

[ftsharp]

In 1826, Karl Ernst von Baer discovered that mammals start their lives from eggs. One supposed difference between us and the animals had to be retracted! Von Baer went on to study the embryonal development of animals, and discovered the blastula stage and the notochord. Poetry by Tom Sharp.

[daberh]

Y’all have no idea how fun it's to be a healthcare student and a Sonic fan. Bc tell me why am I studying a morphogen called Sonic hedgehog that helps the right side of the body develop properly? Haha. How fascinating

[oobertscoobert]

i just. I really love how humans started out as a cell doing Nothing Much in The Wet, then we slowly accumulated more cells and more organs and more complicated brains, we had gills and webbed digits and tails, we slowly gained bones and hair, adapted for life on land, got bigger and bigger, smarter and smarter, we developed language, started walking bipedally…

TWICE!!!

[scienceguy22]

The mother is her own fraternal twin.

This story is mind-bending. In the over 40 years since I became a scientist, I never came across anything like the two cases I'll tell you about. Let's start with a woman, Karen Keegan, in her 50s, who needed a kidney transplant. Her husband & two of her sons had been tested to see if they might be compatible donors. It was during this process that it was discovered that these two sons were not genetically related to Keegan, despite the fact that they were her own children she had given birth to. Keegan's third son, who was too young to be a kidney donor, was then tested. As it turned out, he was a DNA match.

In 2002, a young mother named Lydia Fairchild in Washington state applied for financial assistance after separating from the father of her children. The state required genetic tests to support the claim, but as it turned out, this was the start of a legal & scientific journey that surprised everyone. The maternity test was not a match, suggesting that the mother was not biologically related to her own children—children, mind you, that she definitely remembered giving birth to. When the DNA results indicated Fairchild was not biologically related to her children, the first recourse for lawyers & social workers was to accuse her of lying, thus committing welfare fraud. The children were clearly related to their father, Jamie Townsend, so Fairchild must not have been truthful about her relationship with him.

DNA evidence was considered uncontestable—it didn't matter that Townsend confirmed Fairchild's story or that she could produce photographs of herself with the children throughout their lives. At the time, she was due to give birth to her & Townsend's third child, so a court officer was reportedly ordered to be present to physically witness the delivery. DNA testing on that child told the same story: the child was a genetic match for the father but not for Fairchild. Not understanding how the DNA evidence could possibly be misleading, the judge in the case maintained that some sort of deception must have been happening on the part of Fasiorchild. However, the evidence was enough to convince lawyer Alan Tindell to represent her. Swabs from Fairchild's cervix revealed a DNA lineage that matched her children, whereas DNA collected from her cheek, hair, skin & blood produced a negative result. That's when Fairchild's mother also put forward samples that proved to be a biological match as the children's maternal grandmother. The case against Fairchild was eventually dismissed, and the whole affair of Fairchild & Keegan has prompted a reckoning with the reliability of DNA evidence in the U.S. legal system.

So what is going on here? It turns out that both these mothers were chimeras. The word "chimera" comes from Greek mythology: a creature made of a lion, a goat & a serpent. Biology borrowed the term to describe organisms made of mixed origins, in these cases, the mothers'. It all started with Fairchild and Keegan's mothers, who had two eggs that were ready to be fertilized at the same time. After having sex with their partner, each egg was fertilized by a different sperm. Two fraternal embryos began to grow, but instead of becoming twins, the embryos fused into one baby. One baby was born (one being Fairchild and the other, separately, Keegan). So inside the moms, some tissues came from Embryo A & some tissues came from Embryo B. This created a chimera—a person with two DNA identities—explaining the confusion of DNA matching for their children. A DNA test using her blood (Embryo A) says, "You are not the mother." But she is! The test just sampled the source to confirm DNA inside her. When her cervix was sampled, it came out as a positive match. The DNA of Fairchild's reproductive tract came from Embryo B, one of two fraternal embryos that fused to form her.

Chimerism is extremely rare—estimated at less than 1 in a million. There have been only a few dozen confirmed cases in medical literature. Chimerism breaks the rules that every cell in your body has the same DNA. In forensics & the law, chimerism confuses maternity/paternity tests, & in medicine, it complicates donor matching. For biology, it reveals early human embryos are more flexible than we assumed. Cell lineages can intermix in surprising ways. "One genome per person" is not a universal rule. The incidents do not mean a twin pregnancy; it's just one person with two genomes, hence the term "tetragametic"—2 eggs & 2 sperm. Each egg still only gets one sperm (there's no egg being fertilized by two sperms)—that would be lethal. Instead, you have two normal fertilizations happening side by side—the unusual part is the fusion of the two embryos afterward. Chimerism happens to one child at a time. It's a one-off developmental accident.