بسم الله الرحمن الرحيم دمج الأجنة Chimera

-A genetic animal or Tetra Parental animal or Allophonic. Introduction The word of Chimera meaning with the Greeks is a fictional animal form his lion's head and body goats and monster tail, but at the present time is a mixing of cells from more than one embryo in the early stages of embryonic development. A method by which to produce embryo or organism made ​​up of more than parents and so-called term in -A genetic animal or Tetra Parental animal or Allophonic. A sculpture of a chimera on the Piazetta in Venice

Historical view: The work of Chimera in mammalian embryos was done in more than one type of species such as in mice by Tarkowski in 1961 and Mintz in 1962 then in Rat by Nicholas & Hall in 1940 and Mayer & Fritz in 1974 and in rabbits by Gardner & Mayer in 1974, and in sheep by Tucker and his staff in 1974. (Carole Fehilly and Steel Willadsen(1982)( they fuse sheep and gaot). This work not done only in mammals but carried out in birds also and other animals.

Chimera production methods 1- خلط جنينين بنفس العمر من التفلج Aggregation of embryos at the same age of cleavage 2- حقن البلاستوله بكتلة الخلايا لجنين آخر Blastocyst injection by inner cell mass of other embryo

1- خلط جنينين بنفس العمر من التفلجAggregation of embryos at the same age Is the integration or mixing of two embryos at a certain stage of cleavage in the same phase and the first time been used by Tarkowski in 1961 and Mintz in 1962 where he was mixing two mice embryos in 8 cell stage, then cultured in medium for 24 hours ,later formed one Blastuola from two embryos with one inner cell mass tissue (ICM), then the blastula was transferred to the uterus of another female, and produced mixture progeny formed from different mice strain black and white Figure (78).The chimera when they mated they produce either black or white embryos. Why?

The chimera when they mated they produce either black or white embryo Why?

Blastula injection with another inner cell mass 2- حقن البلاستوله بكتلة الخلايا لجنين اخر Blastula injection with another inner cell mass This methods were used by Gardner in 1968 to 1978. Where injected specific embryo inner cell mass in the other embryo in blastula stage. After the merger of the cells injected with the inner cell mass of the recipient blastula and then transfer to the uterus of another female.

The image under the microscope for precise injection of cell from the inner cell mass, Black mice embryo in (blastula) white. Pictures of (chimaera) mouse, the white spots have appeared from the injected cells in Blastula.

التميز الجنسي أثناء دمج الأجنة Sexual differentiation in chimerric embryos ترى عند دمج جنين يحمل xy مع جنين يحمل xx ماذا سوف يكون جنس الجنين الناتج؟ To answer this question, some researchers have had to explain this phenomenon during the integration of embryos, it is expected that you get half of the embryos that have been incorporated carry xx / xy genes, or to be sterileعقيم , but it is striking that most of the integration in mouse embryos which produced offspring is not sterile and does not involve hermaphroditeخناث , they be either male or female (though carry xx / xy in cells).

There are two possibilities to explain this phenomenon, is that the sex cells formed in sex organ that sex xx / xy, they will die later and do not produce eggs xx but produces sperm xy because these cells xx will enter meiosis and disappear later, therefore it is expected in these types integration of the embryos to have a greater proportion of males than females. Krystof Tarkowski has examined the non-sterile males resulting from the merger and actually found that bone marrow cells which contain chromosomes xx / xy, But Beatrice Mintz found an equal proportion of male and female in embryos that have been merged.

فمن هذه التجارب يتضح أيضا أنه يمكن دمج 3 اجنة بنفس العمر مع بعض لإنتاج جنين واحد مثلا في الفأر. تعتمد على الصفات الوراثية الداخلة في إنتاج الدمج فيصبح الجنين مثلا ذو ست أباء Hexa paternal chimera ES cell: HM1129P2/Ola (Aw/Aw, pTyrc-ch/pTyrc-ch) ES cell: 129/SvJ X 129S1/00090 Blastocyst: C57BL/6 (a/a, C/C)

Different embryos integrateدمج الاجنة المختلفة النوع او الجنس An integration of two embryos from a particular spieces with embryo from other spieces, such as sheep with goats or wild mouse with house mouse. It must be the placenta tissue formed from embryo cells consisting of cells of receiving the same mother. فقد تم مثلا دمج جنين ماعز مع خروف حيث تم زراعة ذلك في إحدى الإناث ولكن لكي تتم هذه العملية فعند دمج الجنينين لابد من دمجهم مع جنين آخر يحمل نفس النسيج الغذائي Trophoblast لتكوين المشيمة من نوع الأم المنقول إليها حتى لا يتم رفض الجنين المنقول.

When you merge 8 cells embryos of goat with sheep embryo 8 cell stage, we need another 16 cell stage embryo from sheep to fused it with them because the older embryo will form the trophoblast cells or placenta of the same mother. Or to inject the goat embryo inner cells mass for example within the blastula of sheep embryos, this sheep embryo transplantation to sheep mother to have the same placenta of embryo and will not be rejection. Both Carole Fehilly and Steel Willadsen) from Cambridge produced chimaera (sheep-goat) in 1982 by injecting the inner cell mass of a goat embryo in the blastula stage sheep embryo then was transferred to sheep mother. It produce chimera the name it as Geep.

They call the sheep –goat chimers as Geep Animal behavior similar to goats grazing with sheep but would prefer, sex cells from the sheep, but sex cells from is unknown and has been able to fertilized sheep but does not work with goats. All chimera when they mated they produce only one type of their chimeric cell, i.e they ether produce sheep or goat but not chimera. So they produce only one type sheep sperm, or goat sperm, but not Geep.

(الشكل 80): صور لخليط مدمج أو كيميرا من ماعز وخروف يسمى قيب Geep)) تم إنتاجه من دمج جنين ماعز مع غنم. التحليل الألكتروليتي لبلازما السائل المنوي يحمل كلا النوعين لكن غالبا من الغنم.

Embryos integrate applications:تطبيقات دمج الأجنة 1- Such technologies provide new genetic material useful in cellular genetic studies. 2- Useful in studies of molecular and injection some genes with fetal cells, or to correct some genetic mutations. 3- Preserve the animals threatened with extinction. 4- Overcome some deadly genetic diseases. 5- Also useful in applied studies to monitor the development of embryos and composition. 6- Useful in biotechnology applied to the production of some antibiotics, and drugs.

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