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.
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.3 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.
- Genetics: 1991 Sept: 129(1):211–9
- Fertility—Sterility—1991 Nov: 56(5):904–12
- Journal of Fertility and Sterility—JC:evf 57(2):346–9