Asexual Birth (Parthenogenesis): Birth Without Fertilization

Introduction:

Parthenogenesis is giving birth to an offspring without sex or coapulation or fertilization. Although plants or lower invertebrates and  vertebrates(including fish) also have a method of fertilization if they are of the type with male and female parts or through pollen grain transfer but still there are vertebrates(including fish), invertebrates and plants that produce an offspring without fertilization

What Is Parthenogenesis:

Its basically an asexual mode of reproducing an offspring or embryo but can occur only in females . The offspring born can be a female or a male depending on the choice of sex determining method in the species in with parthenogenesis is occuring. The genetic make up of offspring will be of its own species with  XX (female) or ZW(male) sex chromosome pair.

The above mentioned mechanism of reproduction is what is naturally occurring in some invertebrates,vertebrates and plants.

However, this does not occur naturally among mammals.

Can Parthenogenesis Occur in Mammals?

Asexual reproduction can occur artificially in mammals. Mechanics told are that any chemical or electrical stimulus but most importantly chemical like Hypercalcemia(excess calcium) may trigger the genetic component of Egg in female and lead to its division.

Outcome Of Parthenogenesis In Mammals:

In mammals genetic material of the offspring is such that half is paternal(from father) and half is maternal(from mother). However to reproduce via parthenogenesis offspring would have double maternal genetic component and none paternal so that would be abnormal or mutated offspring

Use Of Parthenogenesis For Human Race:

Although its even scientifically ridiculous to think that if human race can some how be made to reproduce from asexual mode of reproduction ;but still human race can benefit from it.

Parthenogenesis can be used for production of  embryonic stem cells(basic cells) . These cells can be used for variety of medical conditions including cancer therapy. All that is required is to take unfertilized egg and produce human stem cells from it by parthenogenesis and can be used to transfer these stem cells  to other matched human receipts without being any danger of immune rejection.

Asexual Birth(parthenogenesis):Birth Without Fertilization

Re:asexual birth

Asexual Birth(parthenogenesis):Birth Without Fertilization

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Types Of Reproduction:

Parthenogenesis , Asexual Reproduction And Artificial Cloning:

Difference Between Parthenogenesis ,Asexual reproduction and cloning

Parthenogenesis vs Asexual reproduction(natural cloning):

Though parthenogenesis is a type of asexual reproduction but it has differences:

1)Invertebrates or vertebrates especially exhibiting parthenogenesis are capable of sexual reproduction and mostly due to absence of male partner in mating area they go for parthenogenesis while in other types of asexual reproductions they organism can only go that particular type of asexual reproduction

2)Offspring by any other type of asexual reproduction is genetically similar to its parent that is it is a nature clone of parent. In Parthenogenesis the embryo is not genetically identical

3)Ofspring of parthenogenesis mode of reproduction can have Sexual reproduction. None other asexual offspring can have sexual mode of reproduction

4)Asexual mode of reproduction lacks natural selection while parthenogenesis shows it.

5)I other asexual modes of reproduction ther is absence of gametes in parthenogenesis(ovum) gamete is the requirement.

6)In other asexual type of reproduction genetic material ploidy is same as of parent in parthenogenesis the offspring may have haploid(half)diploid number of chromosomes

Parthenogenesis vs Artificial Cloning:

Cloning makes exact genetic replica of another cell, tissue or organism.

In cloning, the nucleus of a diploid cell from a donor organism is inserted into an enucleated egg cell and the cell is then stimulated to undergo continued mitosis(division of one cell into two that are genetically identical to parent cell) to form organism that is genetically identical to the donor

1)parthenogen is not genetically identical to parent . Clone is genetically identical to parent

2)Cloning does not require genetic material of a gamete(egg cell) rather genetic material of normal body cell is taken . Parthenogenesis require egg cell genetic material

3) In cloning only and only mitosis lead to viable offspring in parthenogenesis meiosis or mitosis any can occur (diploid or haploid offspring)

Parthenogenesis And Human Benefit:

Why Parthenogenesis attracted attention and what benefits human can take?

Mammalian and human parthenogenesis:

By now its clear that parthenogenesis is when in a female  an egg that has not been fertilized by sperm begins to divide on its own to form an embryo or offspring that offspring can only be a female  carrying genetic material only of her mother and can reproduce sexually.This process do occur naturally in invertebrates and some vertebrates(fish)

In mammals and human there is no natural parthenogenesis but can be introduced artificially if egg is stimulated by chemical or electrical trigger

In mammals like mice and monkey such experiments have been able to form abnormal offspring. In mammals o human its not possible to have a normal offspring in this manner as the baby needs to have half of its paternal and half of maternal genes. A mammal created by parthenogenesis would thus have double doses of maternally imprinted genes and lack paternally imprinted genes, leading to developmental abnormalities.

Parthenogenesis attracted attention at first that why males are needed in mammals and human to reproduce while the burden to bear offspring is still on females. If this can happen in other vertebrates or fish why not human?

However in mammals and human  may not be able to reproduce in this manner but embryo can be formed though it will live only for few days but this embryo can be used as source of stem cells for treatment of various heart , liver, brain diseases and cancers.

Stem cells:

Stem cells are undifferentiated cells that have ability to divide and convert into other cells or many different cell types.

Stem cells in an embryo help in formation of different body structures and in organ development like muscles etc

Stem cells in adults like in liver etc will function when there is some injury to liver cells so these cells will differentiate into new liver cells

In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.

Diseases like liver cancer or brain degenerative diseases in which stem cells of that organ are destroyed if new stem cells are given to body will be able to regenerate the organ or nerve.

Plus the concerned issue is the stem cells incooperated must match the genetic marker of the individual who is recepient .So by this method one can obtain stem cells with matching genetic marker(HLA type) and no chances of immune rejection

The phenomenon that leads to virgin birth looks like a promising source of embryonic stem cells. Animal experiments suggest such cells are indistinguishable from normal stem cells.Parthenogenesis  produces embryos that could never become human beings. So destroying these embryos to obtain stem cells would avoid the ethical concerns that have led to restrictions on embryonic stem cell research in many countries.

We cannot have stem cells from a clone(artificial human clone) because a clone itself is capable of life and it has ethical concerns.

Parthenogenesis And Human Benefit:

Doctor Bhai...!!!!!!

Doctor KK