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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!




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Pregnancy Timeline by SemestersDevelopmental TimelineFertilizationFirst TrimesterSecond TrimesterThird TrimesterFirst Thin Layer of Skin AppearsEnd of Embryonic PeriodEnd of Embryonic PeriodFemale Reproductive SystemBeginning Cerebral HemispheresA Four Chambered HeartFirst Detectable Brain WavesThe Appearance of SomitesBasic Brain Structure in PlaceHeartbeat can be detectedHeartbeat can be detectedFinger and toe prints appearFinger and toe prints appearFetal sexual organs visibleBrown fat surrounds lymphatic systemBone marrow starts making blood cellsBone marrow starts making blood cellsInner Ear Bones HardenSensory brain waves begin to activateSensory brain waves begin to activateFetal liver is producing blood cellsBrain convolutions beginBrain convolutions beginImmune system beginningWhite fat begins to be madeHead may position into pelvisWhite fat begins to be madePeriod of rapid brain growthFull TermHead may position into pelvisImmune system beginningLungs begin to produce surfactant
CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development


Fetal Timeline      Maternal Timeline      News     News Archive    Aug 26, 2015 

In molecular biology, an oscillating gene is a gene expressed in a rhythmic pattern or in periodic cycles.
Oscillating genes are usually circadian and identified by periodic changes in the state of an organism.
Circadian rhythms, controlled by oscillating genes, have a period of approximately 24 hours.
Image Credit: Wikipedia






Algorithm identifies gene movement around the clock

An algorithm gives scientists a new way to identify dynamic patterns in oscillating genes, helping define when genes begin to function during fetal growth.

Genes that turn on in precisely timed patterns are known as oscillatory genes. They are essential to cell division, limb formation, and control our circadian rhythms. However, without us having a time-lapse view of when these genes begin to function, oscillatory genes can go unidentified and delay our understanding of molecular functions impacting development.

Now, a study published in Nature Methods describes a new statistical approach, called "Oscope," to help identify oscillating genes. The key to Oscope is examining unsynchronized cells during different cell states - compare results and average when the possibility for oscillation will begin in each. Identifying oscillatory genes using traditional RNA-sequencing requires scientists to choose a known system and identify cells as they synchronize to that system. But this process may mask different types of oscillatory signals developing later, from other signals sychronizing sooner.

With Oscope "we study unsynchronized single cell data so none of the oscillatory systems are disturbed," says Ning Leng, computational biologist with the Morgridge Institute at the University of Madison Wisconsin-Madison (UW-Madison) and co-author on the paper. "This enables us to discover unknown oscillatory signals."

Oscope identifies independent groups of cyclic genes by capturing one "base cycle" oscillation within each. Such technology could open research into genes at the heart of basic development. This type of research needed an interdisciplinary collaboration to solve the question of when genes begin to function, thus combining statistical expertise with cell biology.

Statistical expertise in this project was provided by professor Christina Kendziorski from the Department of Biostatistics and Medical Informatics at UW-Madison. Her group worked in collaboration with the cell biology strengths of stem cell research pioneer — James Thomson — and his group at the Morgridge Institute for Research.

The Oscope software package is offered free to scientists at: https://www.biostat.wisc.edu/~kendzior/OSCOPE/.

"We view this as the first step to understanding oscillatory genes in their relationship to development. What's most interesting is how do genetic regulatory networks govern oscillatory gene expression? How are these signals coordinated in a timely fashion to execute a developmental task?"

Li-Fang Chu PhD, postdoctoral research associate, James Thomson group, Morgridge Regenerative Biology, University of Wisconsin-Madison

The goal of the Thomson lab is to establish a system to detect timing-related genes important in development. The most well understood oscillatory genes are those related to our circadian clock. These genes become active or inactive in tune with the sun cycle and tightly regulate cell proliferation and metabolism over a 24-hour period. They affect disease, the most notable being cancer where cell division is hijacked by cells proliferating out of control. The Oscope technique may help scientists identify the connections between gene cycles and disease cycles.

Although single-cell RNA sequencing is an extremely powerful tool for getting a snapshot of when genes become active, it is less able to trace a single gene over time. Oscope uses high-resolution snapshots of data to identify different gene groups that are potentially changing over time and possibly capture oscillating genes in that group.

"We need a combination of an average signal across many cells for the big picture. We also need single-cell resolution techniques to compare the two in order to figure out which signal may represent true biological variables. The data analysis is very challenging and requires new algorithms, such as Oscope, to perform such complex tasks."

Li-Fang Chu PhD

Oscillatory gene expression is fundamental to development, but technologies for monitoring expression oscillations are limited. We have developed a statistical approach called Oscope to identify and characterize the transcriptional dynamics of oscillating genes in single-cell RNA-seq data from an unsynchronized cell population. Applying Oscope to a number of data sets, we demonstrated its utility and also identified a potential artifact in the Fluidigm C1 platform.

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