Welcome to The Visible Embryo

Home-- -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- -Contact

Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than one million visitors each month.

Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

WHO International Clinical Trials Registry Platform


The World Health Organization (WHO) has created a new Web site to help researchers, doctors and
patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!



Home

History

Bibliography

Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System

Contact The Visible Embryo

News Alerts Archive

Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.

Return To Top Of Page
Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development
Google Search artcles published since 2007
 
Home-- -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs- -- Pregnancy Calculator- --Reproductive System-- News --Contact
 

News Alerts  May 9, 2013--------News Archive

 
Methylation—in which molecules called methyl groups selectively attach to certain areas of DNA and turn off gene activity in those areas—is one of the main markers of gene poising; poised genes enable gene activity later in embryo development.






WHO Child Growth Charts

 

 

 

Dad's genome ready at fertilization, mom's need to catch up

Researchers have discovered that while the genes provided by the father arrive at fertilization pre-programmed to the state needed by the embryo, genes provided by the mother are in a different state and must be reprogrammed to match. The findings have important implications for both developmental biology and cancer biology.

In the earliest stages, embryo cells have the potential to develop into any type of cell, a state called totipotency. Later, this potency becomes restricted through a process called differentiation. As a result, as cells continue to differentiate, they give rise to only a subset of the possible cell types.


"In cancer, normal processes of cell differentiation and growth go wrong, and cells either become arrested at an early state of differentiation, or instead go backwards and are 'reprogrammed' to become more like early embryo cells.

By understanding how cells are normally programmed to the totipotent state, and how they develop from that totipotent state into specific cell types, we hope to better understand how cancer cells misregulate this process, and to use that knowledge to help us devise strategies to reverse this process."

Bradley R. Cairns, co-author of the article, Senior Director of Basic Science, Huntsman Cancer Institute, University of Utah


The research results will be published online as the cover story in the journal Cell on May 9.

Earlier work in the Cairns Lab showed that most genes important for guiding the early development of the embryo are already present in human sperm cells of the father in a "poised" state—turned off, but with attached markers that make gene activation easy. "The logic is that all the important decision-making genes for early development are ready to go," said Cairns. "This poised state is never seen in fully differentiated cells such as skin cells."

In the current study, researchers in the Cairns Lab used high-throughput gene sequencing to comprehensively and precisely analyze DNA methylation patterns in the genomes of zebrafish, which is a common laboratory model both for developmental and cancer biology. Here, they examined egg cells, sperm cells, and four phases of embryonic development: three phases between fertilization and when the embryo's genome becomes active, and one phase after that point.


Methylation—in which molecules called methyl groups are selectively attached to certain areas of the DNA and turn off gene activity in those areas—is one of the main markers of gene poising; poised genes lack DNA methylation, enabling gene activity later in embryo development.

Cairns' group found that the methylation pattern of the soon-to-differentiate embryo is identical to that of the sperm cell.

In contrast, the pattern of the egg cell was initially quite different, but undergoes a striking set of changes to become exactly matched to that of the sperm DNA.

Cairns' work suggests that egg DNA goes through this extensive reprogramming to prepare for the process of differentiation.


"The maternal genes that underwent DNA methylation reprogramming are among the most important loci for determining embryo development," said Cairns. "For example, many hox genes, which determine the body plan and also differentiation during hematopoiesis [the formation of blood cells], are methylated in the mother's genetic contribution and demethylated in the father's, and therefore, also in the embryo."

He said the work added another interesting finding. "We found that the mother's genome takes care of that remodeling on its own, without using the father's genome as a template." Cairns' experiments showed that when the father's genetic contribution was removed, the mother's genome still remodeled itself to the correct state.

"Basically, we're trying to understand how a single cell can make a decision to be any type of cell," said Cairns. "It is a fascinating fundamental question in biology that has implications for all aspects of development and many aspects of diseases such as cancer."

Cairns is a Howard Hughes Medical Institute investigator, a Huntsman Cancer Institute investigator, and a professor in the Department of Oncological Sciences at the University of Utah. He also holds a Jon and Karen Huntsman Presidential Professorship in Cancer Research. Potok is a doctoral candidate in the Cairns Lab at HCI. Co-authors David Nix, PhD, and Timothy Parnell are also affiliated with HCI. Nix is a research assistant professor in the Department of Oncological Sciences at the University of Utah, and Parnell is a research associate in the Cairns Lab.

This work was supported by the Howard Hughes Medical Institute, the Huntsman Cancer Foundation, and NCI CA24014 (for core facilities).

Original article: http://www.eurekalert.org/pub_releases/2013-05/uouh-dgm050713.php