Navigation Links
Cracking the egg

Sexual reproduction is not necessarily sexy (especially when scientists start analyzing it), but it is fascinating. As we all know, the basics entail bringing together an egg and a sperm, a whole lot of cell division and growth, and sooner or later a young organism that carries a mix of genes from both parents. There are many startling events along the way, but one of the most fundamental and important is the transition from unfertilized egg to fertilized embryo.

Think about it: The former is and will remain an egg if left alone, while the latter has within it the means to unleash the dazzling cascade of events needed to create a viable organism. What's already in the egg that enables it to make the transition? How is it the same and how is it different across species? And what changes occur when the egg is fertilized? Scientists led by Drs Barbara Knowles and Alexei Evsikov at The Jackson Laboratory have certainly been thinking about this topic for years. A new paper in the journal Genes & Development presents significant new information about what is happening within a fully grown (pre-ovulatory) egg and some of the changes that occur during transition to the two-cell stage embryo.

The researchers performed a large-scale survey of thousands of fragments of mouse egg cDNA. The cDNA fragments are reverse coded from messenger RNA and therefore indicate which genes are being expressed. They identified 5,400 active genes in the fully grown egg, about a tenth of which are unique to egg cells. Interestingly, the process of getting ready for fertilization requires more genetic activity than early embryo development. There's a far greater diversity of RNAs in the egg cell than in the two-cell embryo, perhaps because the embryo is independent and the pre-ovulatory egg must still coordinate signals with surrounding tissues.

Another discovery was that 80% of the expressed genes identified in mouse eggs are also expressed in the eggs of two other organisms previously studied, a frog and a sea squirt. Obviously early development is a very stable process and many of the crucial steps associated with it have remained the same along the vertebrate evolutionary pathway. But at the same time there's evidence of instability in other areas.

According to Dr. Evsikov, "There's tantalizing evidence for rapid change in a few critical mammalian genes specifically expressed in eggs. These fast-paced changes may pinpoint the molecular mechanisms for reproductive isolation, a primary cause for the origin of new species, and an astonishing diversity of mammals inhabiting Earth."


Source:Jackson Laboratory

Related biology news :

1. Cracking the olfactory code in bees
2. Cracking the perception code
3. Cracking the genetic code for control of gene expression
4. Cracking open the black box of autoimmune disease
Post Your Comments:

(Date:9/28/2015)... 2015 CLEAR, the leading biometric ... traveler service is coming to Austin-Bergstrom International ... a frictionless experience, serious speed and enhanced ... offers our travelers an expedited security screening ... Jim Smith , Executive Director, Austin-Bergstrom International ...
(Date:9/28/2015)... 2015 According to a new ... Product (Scanner & Others), Application (Access Control & Others), ... & Geography Global - Forecast to 2020", published by MarketsandMarkets, ... 3627.90 Million by 2020, at a CAGR of 23.40% ... market data T ables and 66 ...
(Date:9/24/2015)... NEW YORK , Sept. 24, 2015  EyeLock ... will be showcasing its award winning and latest technology ... Anaheim, California . EyeLock,s ... and security with unmatched biometric accuracy, making it the ... DNA.   EyeLock,s platform uses video technology to deliver a ...
Breaking Biology News(10 mins):
(Date:10/12/2015)... 12, 2015 VolitionRx Limited (NYSE MKT: ... study of its NuQ ® blood-based test for early ... of Clinical Epigenetics , the official journal of the ... with Lund University, Sweden ... PhD, Professor of Surgery and Vice-Dean, Faculty of Medicine. ...
(Date:10/12/2015)... ... October 12, 2015 , ... NeuMedics Inc., is a specialty biopharmaceutical company focused ... safely and chronically be administered as an eye drop, announced today it has been ... Clinic and taking place October 25th to October 28th at The Cleveland Clinic, Cleveland, ...
(Date:10/11/2015)... (PRWEB) , ... October 11, 2015 , ... ... Revolution™ Spinal System has been officially launched and multiple surgeries have been completed ... Dr. William Hunter of the Neuroscience & Spine Center of the Carolinas. ...
(Date:10/10/2015)... Am 8. Oktober hat die Kongressabgeordnete ... Kalifornien) ihre Würdigung der International Plasma Awareness Week ... des Kongresses eintragen lassen. Die IPAW wird von ... und ihren Mitgliedsunternehmen unterstützt. Ihre Ziele bestehen in: ... Plasmaspenden weltweit , Würdigung des Beitrages von ...
Breaking Biology Technology: