بسم الله الرحمن الرحيم Parthenogenesis

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1 بسم الله الرحمن الرحيم Parthenogenesis
التكاثر العذري

2 التكاثر العذري Parthenogenesis
Definition Is the ability of oocytes to be produced embryos and individuals without any fertilization, or without participation of sperm or male. Parthenogenesis is divided into two types: - 1- التكاثر العذري الطبيعيِ Natural Parthenogenesis Parthenogenesis is happens in certain species of living organisms and reproduction by sexual and natural parthenogenesis, especially in some types of invertebrates such as some worms, molluscans, freshwater crustaceans (Daphnia) and insects such as bees, ants and wasps.

3 Some animals that produced by parthenogenesis بعض الكائنات ذات تكاثر عذري طبيعي
التكاثر العذري والتلقيح الإصطناعي

4 Some animals that have parthenogenesis صور بعض انواع الكائنات الحية التي يحدث فيها تكاثر عذري
التكاثر العذري والتلقيح الإصطناعي

5 1- تكاثر عذري يحدث من وقت لآخر Sporadic
1- Natural Parthenogenesis in invertebrate التكاثر العذري الطبيعي في الافقاريات Invertebrate parthenogenesis occurs in 3 ways : - 1- تكاثر عذري يحدث من وقت لآخر Sporadic This type occurs with irregular shape in terms of timing, may depend on season and availability of environmental conditions, this type of parthenogenesis was noted in virgin grade squamous wings as in the worm bedدودة القز Ghaz (Bambyx mori) and individuals resulting from this type are females.

6 3- تكاثر عذري دوري Cyclic
2- تكاثر عذري مستمر وثابت Constant This type happens regularly and the type of individuals resulting from this type are males as in the bees النحلand the individual resulting has half the number of chromosomes (1n). 3- تكاثر عذري دوري Cyclic This type occurs with a regular shape, after every normal sexual reproduction occurs parthenogenesis and the example of this is aphid from Aphidiae species.

7 تكاثر عذري دوري Cyclic Parthenogenesis
التكاثر العذري والتلقيح الإصطناعي

8 2- Natural parthenogenesis in vertebratesالتكاثر العذري الطبيعي في الفقاريات
Occurs in some vertebrate species, as in some fish, amphibians and lizards, which overcome the process of doubling the genetic material or chromosomes in different ways, in lizards there are approximately 15-type, parthenogenesis occur in them as in the lizard سميديفورس (Cnemidophorus uniparenes) سحلية سوطية الذيل أحادية الجنس which reproduce by parthenogenesis only, they have no males in these species, but females practiced the mating behavior among themselves without male or fertilization.

9 طريقة التكاثر العذري في سحلية سوطية الذيل(Natural parthenogensis Cnemidophorus uniparenes)
In mating season, females with low concentration of estrogen after ovulation play the role of the male and jump on the female that in the process of ovulation, and so the cycle continues between two females one play the role of the male (with low estrogen ) and the other play the role of the female (with high estrogen) (Figure 58) , and the eggs which produce by parthenogenesis in lizards produces only females. There is also a strain of turkey birds سلالة من الديك الرومي Reproduce by naturally parthenogenesis and the resulting embryos are males and the male can reproduction and produce both male and female.

10

11 صورة لسلالة من ذكر الديك الرومي نتج من تكاثر عذري طبيعي عند تزاوجه هذا الذكر فإنه ينتج نسبة متساوية من الذكور والإناث.

12 2- التكاثر العذري الإصطناعيArtificial Parthenogenesis
This type of parthenogenesis does not spread among the organisms in the normal case, but scientist can do parthenogenesis experimentally by stimulating the ova to inter cell divisions and form embryos without the contribution of sperm to produce full developed individual members.

13 * Methods of artificial parthenogenesis
Researchers in the field of experimental embryology such as (Whillim Ruox, Epele, Hertwing, and Loeb) try to produce embryos in organisms, that originally there is no parthenogenesis breeding, by means of mechanically as puncture of eggs of frogs by needle or by low weak electrical stimulation of the eggs or by placing eggs in a solution containing some chemical components that are active ion-exchange membrane on both sides of the egg (such as potassium, sodium, calcium chloride) or weak organic acids (such as lactic acid and fat solvents as ether, acetone, and alcohol in low concentration).

14 Artificial parthenogenesis in echinoderms (sea urchin)
In the types of echinoderms (sea urchin) eggs cannot produce an embryos without fertilization under natural conditions, but when these eggs exposed to special treatments, they begin the process of cleavage and form embryos which is known artificial parthenogenesis. To make the parthenogenesis, they put the eggs of sea urchin in a low-salt solution for a short period leads to occurs of a cleavage process in the egg and produce embryos.

15 3- The central body and strings of the spindle division and cleavage
Factors that control the parthenogensis processالعوامل التي تتحكم في التكاثر العذري To induce the parthenogenesis process, mainly three factors must be overcome, which occurs during normal sexual reproduction between sperm and egg are: 1- The mechanical stimulation of the oocyte that result from contact of the sperm with the ova. 2 - Provide a second number of the chromosome set any binary number of chromosomes (2 n) 3- The central body and strings of the spindle division and cleavage

16 1-:The mechanical or chemical activation of oocytes
The treatment with chemicals or acupuncture with needle minutes or even electrical shock to the oocyte is a catalyst for the oocyte membrane to complete the meiosis II cell division. The mating behavior that occurs among female lizards flagellar tail with parthenogenesis, this breeding behavior, urges on the process of ovulation is also a mechanical stimulus to activate the eggs.

17 Also found that when put the sea urchin eggs containing a large germinal disc and the animal pole appearing a notch or a clear reduction (Figure 60). During the treatment of these eggs and place it in the low concentration for a short time, it can not be activated soon and it seems to rotate shape and the ova fertilization membrane is formed, as a result of the characteristic low osmosis between the solution concentration and the egg cytoplasm (high concentration somewhat). This is a stimuli to the process of ionic chemical exchange between the cytoplasm of the sea urchin egg and the solution.

18 It has been observed experimentally that the pricked of unfertilized amphibians ova with a sterilized needle, it activates the ova and begins to cleavage. This mechanical stimulate works to flow of sodium ions into the oocyte and release of calcium ions to initiate the cortical granule reaction in the oocytes. Which lead to the completion of the 2nd meiosis division and producing the 2nd polar body.

19 شكل (60): التكاثر العذري الإصطناعي في بويضة قنفذ البحر بواسطة التنبه الكيميائي عند تعريض بيض قنفذ البحر غير المخصب لمحلول ملحي منخفض لمدة قصيرة فإن البيض تختفي فيه الثلمة ويصبح كامل الإستداره مما يدل على انه كأنه بيض مخصب.

20 شكل (61): التكاثر العذري الإصطناعي في بويضات قنفذ البحر بواسطة التنبه الكيميائي عند تعريض بيض قنفذ غير المخصب لمحلول ملحي منخفض لمدة طويلة فإن البيض يدخل مرحلة التفلج تصبح فيها عدة أنويه( ثلاث أو اثنتان) من الجسم القطبي الأول أو الثاني أو نواة واحد هي نواة البويضة الناضجة الناتجة من الانقسام الاختزالي الثاني. والبويضات المتفلجة التي تحتوي على نواتين فقط هي التي تنمو بشكل سليم والبقية تنتج أجنة غير سليمة.

21 2: The nucleus of polar body to obtained the second number of chromosomes
It is known that eggs contain the half the number of chromosomes (1 n). So how can the eggs with a haploid set (1 n) of chromosomes become a diploid chromosome sets (2 n). The nucleus of the polar body is alternative of the male nucleus. When meiosis occurs, the second polar body separated from the ova and then come back and merge with the nucleus of the ova nucleus to complete the binary number of the chromosomes (2 n).

22 2-The 2nd polar body nucleolus instead of the sperm nucleolus:
The interpretation of artificial parthenogenesis: تفسير طريقة حدوث التكاثر العذري 2-The 2nd polar body nucleolus instead of the sperm nucleolus: The ova in the female ovaries are in first meiosis division and some of them complete the first meiosis before ovulation to produce a secondary oocytes and the first polar body. Then in the oviduct they complete 2nd mioses division to produce the mature ova and 2nd polar body. The second polar body some time did not get out of the ova or reinter the ova and work instead of the sperm nucleolus, to retain the 2n. (Why not the 1st Polar body)!

23 In vitro production of parthenogenesis in mammals طريقة عمل التكاثر العذري الاصطناعي في الثدييات في الطبق التكاثر العذري والتلقيح الإصطناعي

24 التكاثر العذري في سمك القرش (راس المطرقة ) Parthenogenesis in hammerhead shark
الحيوان المنوي لسمك القرش (المطرقة) احيانا ينشط البويضة لكن لا تدخل نواته الى داخل البويضة . التكاثر العذري والتلقيح الإصطناعي

25 Why parthenogenesis in Lizard produce only female and birds produce male only
This explains to us, that embryos resulting from eggs parthenogenesis in lizards are always female, because eggs contain sexual chromosome is X only. When the egg is meiosis divided and then fusion of the ova with the 2nd polar body, back to form the 2n and the embryo it will be female (XX). As well as, the parthenogenesis in chicken eggs turkey produces males only, because birds differ from mammals, the sexual chromosome structure of male is (ZZ) and female is (ZW), When meiosis division is occurs the one chromosome going to the ova and other to 2nd polar body Z.

26 If the secondary ova take the chromosome Z and complete the second meiosis division to produce the mature egg and second polar body and did not separate or back to merge with the nucleus of second polar body to produce (ZZ) or (WW). But (WW) doesn't complete the growth because chromosome (W) like chromosome Y did not contains the essential genes for growth or development so (WW) embryo will die or not produced so only (ZZ) embryo will produced as male.

27 Parthenogenesis from the 2nd polar body (in fish and birds) (why cant be produced from the 1st polar body?لماذا لا يمكن ان تنتج من الجسم القطبي الأول التكاثر العذري والتلقيح الإصطناعي

28 لماذا لا تتكاثر الثدييات عذريا؟
Why Jeuses cant be produced from parthenogenesis? لماذا لا يكون عيسى علية السلام لا يكون قد نتج من تكاثر عذري؟ Parthenogenesis is the production of individual without participation of sperm, and because human ova is (XX) and oocytes and polar bodies are (X) and if they produce by parthenogenesis they will produce only females (XX). Way mammals cant produce parthenogentically? لماذا لا تتكاثر الثدييات عذريا؟ It was done by experimentally in mice and it reach the somite only and died so in mammals the paternal gens are important during early embryo development التكاثر العذري والتلقيح الإصطناعي