Sentences with phrase «polar body»

While it may be interesting to speculate that your twins are similar, but not exactly identical, there's no way to know for sure if they are polar body twins.

Neither the speedy results nor the large polar bodies necessarily point to problems with the eggs, she says.

Each egg randomly discarded all but one of the copies by pushing the extras out in two blobs, called polar bodies.

In the new study, Sunney Xie of Peking University and Harvard University teamed up with Qiao and Fuchou Tang of Peking University to develop a method for sequencing the entire genomes of polar bodies — cells that arise as a byproduct of egg cell division and often die later on.

Thanks to further probing aided by an electron microscopy technique developed at EMBL by Yannick Schwab's lab, the scientists found that mother centrioles are expelled into polar bodies thanks to little appendages that centrioles acquire as they mature.

Where a zygosity test can confirm whether twins are monozygotic or dizygotic, companies that perform zygosity testing to determine twin type do not offer a test for polar body twins.

To create an egg, a progenitor cell called an oocyte divides into two daughter cells: a hulking egg cell and a wimpy polar body.

The researchers believe the hammerhead shark reproduced by a type of asexual reproduction called automictic parthenogenesis, whereby an unfertilised egg is activated to behave as a normal fertilised egg by a small, nearly genetically identical cell known as the sister polar body.

In the case of the Komodos, though, polar bodies evidently acted as sperm and turned ova into embryos.

Because polar bodies are dispensable for human embryonic development, they can be safely removed without harming the embryo.

This is called the first polar body, and it defines one of the earliest discernible landmarks in the developing egg.

There are no observed cases of polar body twins and no method to identify or confirm or polar body twinning.

Half identical twins, or polar body, occur when one egg splits in two before fertilization.

They made these clones by a process called automatic parthenogenesis: The egg is formed normally (with half the species» usual number of chromosomes), then fertilized by the «polar body,» a cell that is created during oogenesis and contains the same gene copies as the egg, resulting in the shark having half the genetic variation of its mother.

One daughter centriole is also dragged into a polar body, leaving the other daughter centriole alone in the egg cell.

She found that the egg cell expels the two mother centrioles, jettisoning them into the two «polar bodies» that also serve as dumps for its surplus genetic material.

Another staining technique called comparative genome hybridisation (CGH), which labels all chromosomes, has previously been used to analyse abnormalities in the polar body — a chromosome - containing sac expelled from the egg shortly after fertilisation.

Because the unfertilised egg and the polar body both contain only half of the mother's genes — and the same half — not only did the pup not get any genes from a father, it also only got half of its mother's genetic diversity.

In the case of females, the final stage of meiosis leads to the creation of one cell that becomes the viable egg and another cell called a polar body, which is typically degraded.

Normally, a smaller cell called a polar body pinches off from the egg.

In the new experiments, the polar bodies were abnormally large, which to Saitou suggests that the egg hasn't matured properly.

Oogenesis, the biological process of making an egg cell, typically also yields a polar body — a mini ovum of sorts, containing a duplicate copy of egg DNA.

Normally, this polar body shrivels up and disappears.

Polar bodies are small cells created and usually discarded when an egg is formed, with the egg receiving half the chromosomes and the polar body the other half.

Parthenogenesis is thought to happen when an egg is fertilised by another of the animal's cells called a polar body, says Fields.

By extracting and testing the polar bodies, Verlinsky and his colleagues could see which genes had been thrown out, deduce what was left in the egg, and pick out the healthy candidates.

Albertini's group now suggests not only that these outside cells tell the egg where to locate the polar body — and, therefore, the nucleus and spindle — but also that their plumbing lines soften up the egg cell's rind in the opposite, or vegetal pole, to increase the odds that sperm will penetrate the hemisphere opposite the nucleus.

«We were able to study, in human oocytes, where the chromosomes were in relation to the polar body,» Albertini said.

«It's nice that they are able to reuse the material [from the polar body], but you still need a donor egg,» he says.

Although the probability is very low, the take home message is that for clinical purposes, we should focus on the transfer of single spindle or a polar body, which would carry less mitochondria than the standard transfer of two pronuclei after fertilization.

Oocytes with a first polar body were enucleated manually in the presence of 7.5 µg / ml of cytochalasin B.