- Scientists from The University of Bath have
found that when parthenogenotes were injected with sperms, they developed into
- The success rate of development of
parthenogenotes into healthy offspring was found to be 24%, earlier it was
believed to be 0%.
- This study could aid in improving infertility
treatments and for breeding endangered animals.
Egg cells can be induced to develop into
embryos without a sperm and these cells, called parthenogenotes, do not survive
for longer than a few days.
Scientists from The University of Bath have
now shown that mouse parthenogenotes injected with sperm can develop into
healthy baby mice with a 24% success rate. This study brakes the commonly
acknowledged belief that embryos could develop only from egg cells.
‘Embryos can develop from non-egg cells.’
Uniparental egg cells that develop into
embryos, parthenogenotes, are a source of embryonic stem cells
used for medical as well as for research purposes. Since these cells do not
survive for a period longer than a few days, they have never been considered to
be fully functional embryos. They lack the ability to develop further as they do
not have the necessary instructions for the developmental processes dictated by
Obtaining embryonic stem cells from
parthenogenotes is, therefore, currently considered ethical. The latest
research by Dr. Toru Suzuki and colleagues from the Laboratory of mammalian
Molecular Embryology at The University of Bath might displace this theory.
This study is the brain child of Dr. Toru
Suzuki who worked along with The University of Regensburg's Fraunhofer
Institute for Toxicology and Experimental Medicine (Germany).
Development of the Embryo on Sperm Injection
The scientists from the Department of
mammalian Molecular Biology have discovered a way to inject sperms into
parthenogenotes. This resulted in the growth and development of 24% of the
embryos into baby mice. Earlier, 0% of parthenogenotes lived for longer than a
few days while the success rate for nuclear transfer cloning cells was found to
The mice that were born out of this method
were found to be healthy, the only difference being that the epigenetic markers
that were identified followed a different pathway when compared with normal
and growth of embryos.
This study is published in the journal Nature
and the senior author of the study, Dr. Tony Perry, a
Molecular Embryologist said "This is first time that full term development
has been achieved by injecting sperm into embryos. "It had been thought
that only an egg cell was capable of reprogramming sperm to allow embryonic
development to take place.
He further added, "Our work challenges
the dogma, held since early embryologists first observed mammalian eggs around
1827 and observed fertilisation 50 years later, that only an egg cell
fertilised with a sperm cell can result in a live mammalian birth."
Similarity of Parthogenetic Stem Cells with
Embryonic Stem Cells
The stem cells that are derived from parthenogenotes
are very important for medical as well as for research purposes. A study by Dr.
Liu W and colleagues titled " Directing the Differentiation of Parthenogenetic
Stem Cells Into Tenocytes for Tissue-Engineered Tendon Regeneration." and
published in the Journal Stem Cells Translational Medicine
, outlines the
properties of parthenogenetic stem cells and their similarities with embryonic
The properties of the parthogenetic stem
- Ability for self
- Ability to
differentiate under invivo as well as invitro
The study also showed that parthenogenetic
stem cells were a good source of tissue engineered tendon. The similarity with
embryonic stem cells could be an indication of their potential to develop into
healthy offspring when injected with sperm at the right time.
Potential Uses of the Study
- It could be used to breed animals using non-egg cells and
injecting the sperm.
- It could be used to improve infertility treatments.
When sperms are available in low numbers, the eggs could be induced to develop
into parthenogenotes and sperms could be injected only into well developed
- It could be used to breed endangered
The study provides an insight into epigenetic
mechanisms that are involved in the development of these non-egg cells into a
well developed offspring. Pathways, that were earlier unknown, were identified
during this study.
The Medical Research Council (UK) funded this
study in part and Dr. Paul Colville-Nash from the MRC said "This is an
exciting piece of research which may help us to understand more about how human
life begins and what controls the viability of embryos, mechanisms which may be
important in fertility
It may one day even have implications for how we treat infertility, though
that's probably still a long way off."
The study on humans hasn't yet begun but this
study is a conclusive step towards better infertility treatment.
- Liu W, Yin L, Yan X, Cui J, Liu W, Rao Y, Sun M,
Wei Q, Chen F "Directing the Differentiation of Parthenogenetic Stem Cells Into
Tenocytes for Tissue-Engineered Tendon Regeneration" Stem Cells Transl Med.
2016 Aug 18. http://www.ncbi.nlm.nih.gov/pubmed/27538430