Key to the technique: replacing the defective mitochondrial DNA with healthy genetic material from the egg of a second woman.
Next, Dr. Edwards removed the DNA from the egg of another cow, leaving behind egg cytoplasm.
In 18 of the 33 females crossed, the size sorting of the eggs from the first sibship reflected the egg ploidy (left part of Additional file 3; the 15 females without size data either laid just one size of eggs, or the attempted egg sorting did not reflect differences in genomic content).
The third stage is ' Sounds can be heard coming from the egg! ' The fourth stage is the egg hatching.
The probability of a painted turtle surviving from the egg to its first birthday is only 19%.
The first injection was done to promote maturation of the eggs and the second one was to induce the release of eggs from the ovary (Shan Jian 1985).
Eggs of one of the strains (Mon) were kindly supplied by Nancy Adams (Monsanto), while eggs of the second strain (Ben) were purchased from Benzon Research (Carlisle, PA).
In type 2 (absence of egg nucleus), the egg nucleus is released from the egg together with second polar body nucleus and only the sperm nucleus remains in the egg.
In both species, laying date significantly affected only the sex of the first egg and not the second egg.
Furthermore, we incorporated the sex of the first egg laid in clutch 2, which might have resulted from follicle abortion and latency to oviposition (days between pairing and first egg, clutch 2) as predicting variables.
