It stops the development of the egg (if eggs are simply destroyed, the goose will often lay more).
When cloning works, the adult cell takes over the development of the egg, using its genes to direct the development of the embryo, fetus and newborn, which are the genetic match of the adult that provided the original cell.
Whereas sexual reproduction requires sperm for fertilization, parthenogenic reproduction in this species involves sperm only to stimulate the initial development of the egg; the sperm's genetic material is not used.
Direct development of the egg, in which the larvae undergo their development within the egg membranes and emerge as tiny froglets, occurs in many species, in a dozen or more families (such as Leiopelmatidae, Pipidae, Leptodactylidae, Bufonidae, Brachycephalidae, Hylidae, Myobatrachidae, Sooglossidae, Arthroleptidae, Ranidae, and Microhylidae).
Last year, a group led by veterinarian Woo Suk Hwang and gynecologist Shin Yong Moon at Seoul National University reported the first derivation of ES cells from human nuclear transfer (Science, 12 March 2004, p. 1669 --a process that involves replacing an oocyte's nucleus with one from a different cell, and then chemically kick-starting development of the egg.
The development of the egg chamber, referred to as oogenesis, can be divided into 14 morphologically distinct stages; reviewed in [24].
This is the greatest forward step since the development of the egg-beater and promises to open up some really enchanting vistas if other outfits accept the challenge.
In reptiles copulation may stimulate ovulation, occur simultaneously with ovulation, take place within an hour to a week of ovulation (presumably the most frequent situation), or occur months prior to complete the development of the eggs and their ovulation.
"Normally the nest is built in a tree and there is a great amount of drainage and there is no contact with a possible cold surface that could interfere with the proper development of the eggs," he wrote in an e-mail.
Once the relative humidity is greater than 40%, it has little effect on the rate of development of the eggs.
Temperatures between about 15 and 25 °C seem suitable for development of the eggs are typically required for the egg stage [43].
