Related Experiment Video
Updated: Jun 21, 2026

Human Pluripotent Stem Cell Based Developmental Toxicity Assays for Chemical Safety Screening and Systems Biology Data Generation
Published on: June 17, 2015
Variability in human embryonic development and its implications for the susceptibility to environmental teratogenesis
1Department of Anatomy and Developmental Biology and Congenital Anomaly Research Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan. shiota@hq.kyoto-u.ac.jp
Abstract:
Considerable variability is observed in the size and developmental stage among human embryos at a given gestational age, suggesting that prenatal development does not proceed at the same speed in every embryo. Such variability in embryonic development seems to occur in many (probably all) animal species, and is probably a normal "biologic" phenomenon to some extent. In the case of humans, some other factors (e.g., maternal memory bias, difficulty in assessing the timing of ovulation and fertilization) make it more difficult to assess the developmental stage of embryos in utero. Such facts related to human embryonic development should be taken into account when the teratogenic risk of a human embryo is considered.
More Related Videos
Related Concept Videos
Teratogenicity
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Gene-Environment Interactions
Heritability
Embryonic Stem Cells
ES cells are grown in a culture medium where they can divide indefinitely, creating ES cell lines. Under certain conditions, ES cells can differentiate, either spontaneously into a variety of...
Genetic Variation
Genes exist in different versions called alleles, which...

