........................................................................
>And I am sure in his next email Dr. Rauf is going to tell us a scientific
>medical research article published in an international, peer-reviewed
>medical journal, where we can read about these things.
Yes, indeed, and the reason you are sure is that you know Dr. Rauf never
says something for which he has no proof. Thanks for that trust.
Parthenogenesis; non-sexual reproduction i.e. development of the ovum into
an individual without fertilization by a spermatozoon.
It is very common in the insect world and in fish, and is routine in animals
such as the aphids. Among the reptiles there is strong evidence that
parthenogenesis can be a successful strategy for lizards in an environment
with low and unpredictable rainfall.[1] In the Lancet in 1955 it was
reported that
a woman had a daughter where parthenogenesis could not be disproved. It has
been produced in animals experimentally. There is, however, no certain
record of the birth of a parthenogenetic animal. The most that has been
achieved is that parthenogenetic mice and rabbit embryos have developed
normally to about
halfway through pregnancy but have then died and been aborted.
In humans a recent research study was carried out on The development
and systematic study of the parthenogenetic activation and early development
of human oocyte.[2] In this study, human oocyte, both freshly retrieved and
remaining unfertilized after exposure to spermatozoa, were exposed to
alcohol or calcium ionophore and examined for evidence of activation. The
outcome of this study was that human oocyte can be activated
parthenogenetically using calcium ionophore, but at lower rates than seen
for mouse oocyte. Human parthenotes can complete division to the 8-cell
stage. This data raises the possibility that some early human pregnancy
losses may involve oocyte that have been parthenogenetically activated
spontaneously.
An incident of partial parthenogenesis in a human was reported in the "New
Scientist" of October 7, 1995 under the heading, "The boy whose blood has no
father" [3]. In the case of males all cells should have a Y chromosome, but
in this particular case study of a three year old boy the white blood cells
were found to contain only XX chromosomes. The reporter also mentions that
ocassionally, chromosomal females carry one X chromosome which includes the
maleness gene and that the researchers had at first assumed that their case
study was an example of this syndrome. But when they used extremely sensitive
DNA technology they were not able to detect any Y chromosomes in the boys
white blood cells. However, the boy's skin was discovered to be genetically
different from his blood, having both X and Y chromosomes.
A more detailed analysis of the X chromosomes in the boy's skin and blood
revealed that all his X chromosomes were identical and derived entirely
from his mother. Similarly both members of each of the 22 other chromosome
pairs in his blood were identical, coming entirely from the mother. The
explaination given by researchers for this phenomenon is that the unfertilised
ovum self-activated and began dividing itself into identical cells; one of
these cells was then fertilised by a spermatozoon from the father and the
resultant mixture of the cells began to develop as normal embryo. This also
illustrated that the cells created parthenogenetically in mammals are not
always disabled.
Hermaphroditism; a sex anomaly in which gonads for both sexes are present;
the external genitalia show traits of both sexes and chromosomes show
male female mosaicism (xx/xy).
In a study in the Netherlands in 1990 called Combined Hermaphroditism
and Auto-fertilization in a Domestic Rabbit. In this study a true
hermaphrodite rabbit served several females and sired more than 250 young
of both sexes. In the next breeding season, the rabbit which was housed in
isolation, became pregnant and delivered seven healthy young of both sexes.
It was kept in isolation and when autopsied was again pregnant and
demonstrated two functional ovaries and two infertile testes. A chromosome
preparation revealed a diploid number of autosomes and two sex chromosomes
of uncertain configuration.
A study was carried out on a human hermaphrodite at the Department of
Obstetrics and Gynaecology, Chicago, Lying-in Hospital, Illinois.[4]
The objective of this research was to determine the conceptional events
resulting in a 46xx, 46xy true hermaphrodite and to report the first
pregnancy in a 46xx, 46xy true hermaphrodite with an ovotestis.
The design of this study involved chromosome studies performed on patient's
lymphocytes and fibroblasts, red cell antigens, human leucocytes antigens
and the presence of y- chromosome deoxyribonucleic acid were analyzed.
Findings were compared with parental and sibling blood group data.
The result of these studies demonstrated that our patient is a chimera; an
organism in which there are at-least two kinds of tissue differing in their
genetic constitution, thus with dual maternal and paternal contributions.
In addition, despite the presence of an ovotestis, she conceived and
delivered a child.
References for the above:
[1]. Genetics, Sept. (1991) Vol. 129, No. 1. Pages 211-219.
[2]. Fertility - Sterility, Nov. (1991) Vol. 56, No. 5, Page 904-912.
[3] This report refered to D. Bonthron et al. Nature Genetics Oct. (1995).
[4]. Journal of Fertility and Sterility - JC:evf, Feb. (1992) Vol 57, No. 2
Pages 346-349.
I am also reproducing the abstracts of the following papers with the
source without any comments from me.
Source: J Theor Biol 1986 Oct 21;122(4):421-40
Abstract: The problem of the maintenance of anisogamous sex is addressed
by considering the effect of fertilization on the fitness of
parthenogenetic females when such fertilization yields inviable
triploid progeny. We consider four types of parthenogenesis:
(i) apomixis, (ii) homogametic amphimixis, (iii) heterogametic
amphimixis, and (iv) homogametic automixis. Homozygous sexual
populations are genetically stable if males or selection eliminate the
excess females produced by heterozygous parthenogenetic genotypes.
Homozygous parthenogenetic populations are stable if the parthenogenetic
output of homozygotes exceeds that of heterozygotes. In turn, sex can
only invade heterozygous parthenogenetic populations when sexual output
of parthenogens is larger than their parthenogenetic output. The
existence of interior stable equilibria generally requires the
instability of at least one boundary and some degree of heterosis. In
a two-locus model, we study the evolution of mechanisms protecting
either sex or parthenogenesis in reproductively polymorphic populations.
We find that males do not respond to the presence of parthenogenesis
in such a way as to eliminate it, but parthenogenesis is subject to
selective pressures increasing reproductive isolation, and thus the
success of parthenogenesis. The results suggest that reproductively
polymorphic populations are ephemeral
Hermaphrodites
Title: TRUE HERMAPHRODITISM: CLINICAL FINDINGS, DIAGNOSTIC METHODS AND
TREATMENT
Author: KROB-G; BRAUN-A; KUHNLE-U
Address of Author: NATL UNIV MALAYSIA, KUALA LUMPUR 50300 MALAYSIA
(Reprint Address); UNIV MUNICH, KINDERKLIN, W-8000 MUNICH GERMANY
Source: MONATSSCHRIFT-KINDERHEILKUNDE.APR 1996; 144 (4) : 362-368. .
ISSN (International Standard Serial Number): 0026-9298
Abstract
True hermaphroditism is a disorder of sex determination in which ovarian
as well as testicular tis sues are present in the same individual. Most
patients present at birth with ambiguous genitalia; primary amenorrhoea,
gynaecomastia or hematuria are common symptoms in many patients during
puberty. Physical examination, ultrasonography, hormonal stimulation tests
as well as genetic investigations are needed prior to exploratory
laparotomy to determine true hermaphroditism. Sex assignment should be
guided by the anatomical aspect. Female true hermaphrodites are often
fertil (10 pregnancies have been published), in contrast to infertility
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
of male patients. The prevalence of gonadal tumours is 4.6% in 283
patients with a higher risk for patients with a 46,XY karyotype. Thus
the removal of the testicular tissue and replacement therapy at puberty
is recommended. Surgical treatment in true hermaphrodites includes correction
of the external genitalia and resection of the ovarian tissue in male
patients.
You may also find some info from the following web sites as well as paper
http://dauerdigs.biosci.missouri.edu/Dauer-World/Abstracts/Matcostgazette.html
A POSSIBLE COMMON ORIGIN OF Y-NEGATIVE HUMAN XX MALES AND XX TRUE
HERMAPHRODITES
AUTHORS: ABBAS_NE, TOUBLANC_JE, BOUCEKKINE_C, TOUBLANC_M, AFFARA_NA,
JOB_JC, FELLOUS_M
JOURNAL: HUMAN GENETICS, 1990, Vol.84, No.4, pp.356-360
Parthenogenesis: Web References,
http://entmuseum9.ucr.edu/ent010/Lec_05.html
http://www.bio.bris.ac.uk/resource/darwindm.txt
http://darwin.ceeb.uky.edu/ceeb/profs/mooreqg.html
http://avsunxsvr.aeiveos.com/au/rose-mr/87313527.html
I hope this answers all the questions raised in response to my earlier
article specially Jochen who specifically demanded peer reviewed scientific
publication.