Related Experiment Video
Updated: Dec 29, 2025
08:53
Drug Treatment and In Vivo Imaging of Osteoblast-Osteoclast Interactions in a Medaka Fish Osteoporosis Model
Published on: January 1, 2017
9.6K
Transgenic Medaka Identify Embryonic Periods Sensitive to Disruption of Sex Determination
Petra Spirhanzlova1,2, Pauline Trébulle1, Justine Lallement1
1Laboratoire WatchFrog, Evry, Ile-de-France, France.
Environmental Toxicology and Chemistry
|February 1, 2020
Summary
Medaka fish sex determination is sensitive to estrogen and androgen exposure during specific embryonic windows. This research identified key developmental periods for hormonally induced sex reversal, aiding future toxicity screening.
Area of Science:
- Endocrinology
- Developmental Biology
- Toxicology
Background:
- Medaka gonadal development relies on balanced estrogen and androgen levels; disruptions can cause intersex conditions (ovo-testis).
- Identifying sensitive developmental periods is crucial for understanding and assessing the impact of endocrine-disrupting chemicals.
Purpose of the Study:
- To determine the sensitive developmental windows for hormonally induced sex reversal in medaka (Oryzias latipes).
- To establish a transgenic medaka line for efficient identification of female gonadal tissue.
Main Methods:
- Developed a novel transgenic medaka line (42sp50-GFP_ChgH-GFP) for fluorescence-based identification of female gonadal tissue.
- Exposed medaka fry to short pulses of 17β-estradiol (E2) or 5α-dihydrotestosterone (DHT) during early development (days postfertilization 0-12).
- Evaluated phenotypic sex reversal and confirmed with genotyping at 16 days postfertilization.
Main Results:
- The transgenic line exhibited fluorescence in ovaries and liver in response to estrogens.
- Medaka were sensitive to E2 between days postfertilization 1 and 8.
- Susceptibility to DHT occurred during two periods: days 0-1 and days 4-8 postfertilization.
- No sex reversal was observed after exposure on days 11 or 12 postfertilization; effects persisted to at least day 24.
Conclusions:
- Specific embryonic time windows (1-8 dpf for E2, 0-1 dpf and 4-8 dpf for DHT) are sensitive to sex determination disruption in medaka.
- These findings support the use of early medaka embryonic stages for developing screening assays for endocrine disruptors.
Related Concept Videos
02:45The Ratio of X Chromosome to Autosomes
9.3K
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female...
9.3K
01:16In-vitro Mutagenesis
15.9K
To learn more about the function of a gene, researchers can observe what happens when the gene is inactivated or “knocked out,” by creating genetically engineered knockout animals. Knockout mice have been particularly useful as models for human diseases such as cancer, Parkinson’s disease, and diabetes.
15.9K