Another important transgenerational epigenetic inheritance study

This 2019 Washington State University rodent study from Dr. Michael Skinner’s lab found:

“A cascade of epigenetic alterations initiated in the PGCs [primordial germ cells] appears to be required to alter the epigenetic programming during spermatogenesis to modify the sperm epigenome involved in the transgenerational epigenetic inheritance phenomenon.

Following fertilization there is a DNA methylation erasure to generate the stem cells in the early embryo, which then remethylate in a cell type-specific manner. The DNA methylation erasure is thought to, in part, reset deleterious epigenetics in the germline. However, imprinted gene DNA methylation sites and induced transgenerational epimutations appear to be protected from this DNA methylation erasure.

A germline with an altered epigenome has the capacity to alter the early embryo’s stem cell’s epigenome and transcriptome that can subsequently impact the epigenomes and transcriptomes of all derived somatic cells. Therefore, an altered sperm epigenome has the capacity to transmit phenotypes transgenerationally. Experiments have demonstrated that epigenetic inheritance can also be transmitted through the female germline.

Previously, the agricultural fungicide vinclozolin was found to promote the transgenerational inheritance of sperm differential DNA methylation regions (DMRs) termed epimutations that help mediate this epigenetic inheritance. The current study was designed to investigate the developmental origins of the transgenerational DMRs during gametogenesis.

The current study with vinclozolin-induced transgenerational inheritance demonstrates that sperm DMRs also originate during both spermatogenesis and earlier stages of germline development, but at distinct developmental stages. This is a genome-wide analysis of epigenetic programming during gametogenesis for transgenerational sperm epimutations.”

The study’s main hypotheses were:

Following fertilization, the hypothesis is that the transgenerational epimutations modify early embryonic transcriptomes and epigenomes to re-establish the cascade for the next generation.

As the individual develops, all somatic cells have altered epigenomes and transcriptomes to promote disease susceptibility later in life.

Researchers: adopt these hypotheses, and don’t limit your study designs to the F1 children as did:

Don’t stop at the F2 grandchildren like:

Continue studies on to F3 descendants who had no direct exposure to the altering stimulus. Keep in the forefront of your research proposals that there are probably more than 10,000,000 F3 great-grandchildren of DES-exposed women just in the US. “Transgenerational sperm DNA methylation epimutation developmental origins following ancestral vinclozolin exposure”


The transgenerational impact of Roundup exposure

The latest 2019 Washington State University rodent study from Dr. Michael Skinner’s lab found adverse effects in the grand-offspring and great-grand-offspring following their ancestor’s exposure during pregnancy to the world’s most commonly used herbicide:

“Using a transient exposure of gestating F0 generation female rats found negligible impacts of glyphosate on the directly exposed F0 generation, or F1 generation offspring pathology. In contrast, dramatic increases in pathologies in the F2 generation grand-offspring, and F3 transgenerational great-grand-offspring were observed.

The transgenerational pathologies observed include prostate disease, obesity, kidney disease, ovarian disease, and parturition (birth) abnormalities:

  1. Prostate disease in approximately 30% of F3 generation glyphosate lineage males, a three-fold increase in disease rate over controls.
  2. A transgenerational (F3 generation) obese phenotype was observed in approximately 40% of the glyphosate lineage females and 42% of the glyphosate lineage males.
  3. An increased incidence of kidney disease observed in the F3 generation glyphosate lineage females affecting nearly 40% of females.
  4. A significant increase in ovarian disease observed in the F2 [48% vs. 21% for controls] and F3 [36% vs. 15% for controls] generation glyphosate lineage females.
  5. During the gestation of F2 generation mothers with the F3 generation fetuses, dramatic parturition abnormalities were observed in the glyphosate lineage. The frequency of unsuccessful parturition was 35%. To further investigate the parturition abnormalities an outcross of F3 generation glyphosate lineage males with a wildtype female was performed. There were parturition abnormalities observed with a frequency of 30%.

Classic and current toxicology studies only involve direct exposure of the individual, while impacts on future generations are not assessed. The ability of glyphosate and other environmental toxicants to impact our future generations needs to be considered, and is potentially as important as the direct exposure toxicology done today for risk assessment.”

Why isn’t coverage of this study the top story of the world’s news organizations? Is what’s reported more important than reliable evidence of generational consequences to environmental experiences?

Current toxicology practices are a scientific disgrace:

  • What are the hypotheses of practices that only test effects on somatic cells, that don’t look for generational effects of germ cell modifications?
  • Are they selected for their relative convenience instead of chosen for their efficacy?

Why don’t sponsors fund and researchers perform human studies of transgenerational epigenetic inheritance? For example, from Burying human transgenerational epigenetic evidence:

“From the late 1930s through the early 1970s, DES was given to nearly two million pregnant women in the US alone.

Fourth [F3] generation effects of prenatal exposures in humans have not been reported.

Zero studies of probably more than 10,000,000 F3 great-grandchildren of DES-exposed women just here in the US!

There will be abundant human evidence to discover if sponsors and researchers will take their fields seriously. “Assessment of Glyphosate Induced Epigenetic Transgenerational Inheritance of Pathologies and Sperm Epimutations: Generational Toxicology”

Our brains are shaped by our early environments

This 2019 McGill paper reviewed human and animal studies on brain-shaping influences from the fetal period through childhood:

“In neonates, regions of the methylome that are highly variable across individuals are explained by the genotype alone in 25 percent of cases. The best explanation for 75 percent of variably methylated regions is the interaction of genotype with different in utero environments.

A meta-analysis including 45,821 individuals with attention-deficit/hyperactivity disorder and 9,207,363 controls suggests that conditions such as preeclampsia, Apgar score lower than 7 at 5 minutes, breech/transverse presentations, and prolapsed/nuchal cord – all of which involve some sort of poor oxygenation during delivery – are significantly associated with attention-deficit/hyperactivity disorder. The dopaminergic system seems to be one of the brain systems most affected by perinatal hypoxia-ischemia.

Exposure to childhood trauma activates the stress response systems and dysregulates serotonin transmission that can adversely impact brain development. Smaller cerebral, cerebellar, prefrontal cortex, and corpus callosum volumes were reported in maltreated young people as well as reduced hippocampal activity.

Environmental enrichment has a series of beneficial effects associated with neuroplasticity mechanisms, increasing hippocampal volume, and enhancing dorsal dentate gyrus-specific differences in gene expression. Environmental enrichment after prenatal stress decreases depressive-like behaviors and fear, and improves cognitive deficits.”

The reviewers presented strong evidence until the Possible Factors for Reversibility section, which ended with the assertion:

“All these positive environmental experiences mentioned in this section could counterbalance the detrimental effects of early life adversities, making individuals resilient to brain alterations and development of later psychopathology.”

The review’s penultimate sentence recognized that research is seldom done on direct treatments of causes:

“The cross-sectional nature of most epigenetic studies and the tissue specificity of the epigenetic changes are still challenges.”

Cross-sectional studies won’t provide definitive data on cause-and-effect relationships.

The question that remains to be examined is: How can humans best address these early-life causes to ameliorate their lifelong effects? “Early environmental influences on the development of children’s brain structure and function” (not freely available)

Epigenetic transgenerational inheritance mechanisms that lead to prostate disease

This 2019 Washington rodent study found:

“Ancestral exposure to the toxicant vinclozolin induces an epigenetic transgenerational increase in susceptibility to prostate pathology in F3 [male great-grandchildren] generation rats. These results are in agreement with previous studies which found a transgenerational increase in rates of prostatic epithelial atrophy, cystic hyperplasia, and prostatitis in the transgenerational F3 and F4 [male great-great-grandchildren] generations after exposure of F0 [great-great-grandmother] generation pregnant rats to vinclozolin. These effects were accompanied by transgenerational changes in mRNA expression in F3 generation ventral prostate epithelial cells.

A number of previous transgenerational studies have shown no ventral prostate histopathology or disease detected. Therefore, observations suggest ancestral exposure specificity in the ability to induce the transgenerational inheritance of prostate disease.

There was also no increase in prostate histopathology in the directly exposed F1 [male children] or F2 [male grandchildren] generation vinclozolin lineage rats compared to controls.

prostate pathology

The mechanism by which epigenetic transgenerational inheritance affects prostate epithelium involves control of gene expression by DNA methylation and lncRNAs. It will be necessary to determine the exact gene targets of these epigenetic modifications to determine further mechanisms.

Future studies need to investigate if similar mechanisms are at work in human males who have adult-onset BPH or prostate cancer. Ancestral exposures to toxicants and epigenetic transgenerational inheritance may contribute to the development of prostate disease in men today.”

The study’s above bolded sentence added to the evidence that epigenetic effects may skip generations. A study by the same group, Epigenetic transgenerational inheritance of ovarian disease, found in females:

There was no increase in ovarian disease in direct fetal exposed F1 or germline exposed F2 generation vinclozolin or DDT lineage rats compared to controls.

A disturbance in the paradigm of child abuse referenced other studies that found generation-skipping effects.

Serious researchers are closer to discovering evidence for precise mechanisms of epigenetic transgenerational inheritance. It’s well past time that other researchers performing studies like Burying human transgenerational epigenetic evidence take their work seriously enough to truly investigate human evidence for epigenetic transgenerational inheritance.

What are more important funding priorities than such human studies? “Environmental Toxicant Induced Epigenetic Transgenerational Inheritance of Prostate Pathology and Stromal-Epithelial Cell Epigenome and Transcriptome Alterations: Ancestral Origins of Prostate Disease”

Epigenetic causes of sexual orientation and handedness?

This 2018 Austrian human study subject was various associations of prenatal testosterone levels to fetal development:

“The available evidence suggests, albeit not conclusively, that prenatal testosterone levels may be one cause for the association of sexual orientation with handedness. Associations among women were consistent with predictions of the Geschwind–Galaburda theory (GGT), whereas those among men were consistent with predictions of the callosal hypothesis. However, research on the associations between sexual orientation and handedness appears to be compromised by various methodological and interpretational problems which need to be overcome to arrive at a clearer picture.

The GGT posits that high prenatal testosterone levels cause a delay in the fetal development of the left cerebral hemisphere which results in a right-hemisphere dominance and hence in a tendency for left-handedness. According to the GGT, high prenatal testosterone levels entail not only a masculinization of the female fetus, but also a feminization of the male fetus (contrary to neurohormonal theory). Overall, the male fetus is subjected to higher levels of intrauterine testosterone than the female fetus. The GGT is thus consistent with the higher prevalence of left-handedness among men than among women.

The callosal hypothesis applies to men only and assumes, in line with neurohormonal theory, that low prenatal testosterone levels are associated with later homosexuality. According to the CH, high prenatal testosterone enhances processes of cerebral lateralization through mechanisms of axonal pruning, thereby resulting in stronger left-hemisphere dominance and a smaller corpus callosum. Consistent with this, women have a larger corpus callosum than men.”

The study’s Limitations section included the following:

  1. “Limitations of the current study pertain to the self-report nature of our data. Behavioral data may provide differing results from those obtained here.
  2. Assessment of sexual orientation relied on a single-item measure. Utilization of rating scales (e.g., the Kinsey Sexual Orientation Scale) or of multi-item scales, and assessing different components of sexual orientation, would have allowed for a more fine-grained analysis and for a cross-validation of sexual orientation ratings with sexual attraction.
  3. Albeit both our samples were large, the proportions of bisexual and homosexual individuals were, expectedly, only small, as were effects of lateral preferences. Thus, in analysis we could not differentiate bisexual from homosexual individuals. Bisexual and homosexual individuals may differ with regard to the distribution of lateral preferences.
  4. Some effect tests in this study have been underpowered. Independent replications with even larger samples are still needed.”

The largest unstated limitation was no fetal measurements. When a fetus’ epigenetic responses and adaptations aren’t considered, not only can the two competing hypotheses not be adequately compared, but causes for the studied phenotypic programming and other later-life effects will also be missed. “Associations of Bisexuality and Homosexuality with Handedness and Footedness: A Latent Variable Analysis Approach”

Burying human transgenerational epigenetic evidence

The poor substitutes for evidence in this 2018 US study guaranteed that human transgenerational epigenetically inherited effects wouldn’t be found in the generations that followed after prenatal diethylstilbestrol (DES) exposure:

“A synthetic, nonsteroidal estrogen, DES was administered to pregnant women under the mistaken belief it would reduce pregnancy complications and losses. From the late 1930s through the early 1970s, DES was given to nearly two million pregnant women in the US alone.

Use of DES in pregnancy was discontinued after a seminal report showed a strong association with vaginal clear cell adenocarcinoma in prenatally exposed women. A recent analysis of the US National Cancer Institute (NCI) DES Combined Cohort Follow-up Study showed elevated relative risks of twelve adverse health outcomes.

We do not have sufficient data concerning the indication for DES in the grandmother to determine whether adverse pregnancy outcomes in the third generation might resemble those of their grandmothers. Fourth generation effects of prenatal exposures in humans have not been reported.”

This study had many elements in common with its wretched cited reference [25] “Transgenerational effects of prenatal exposure to the 1944–45 Dutch famine” which is freely available at

That study’s Methods section showed:

  1. Its non-statistical data was almost all unverified self-reports by a self-selected sample of the F2 grandchildren, average age 37.
  2. No detailed physical measurements or samples were taken of the F2 grandchildren, or of their F1 parents, or of their F0 grandparents, all of which are required as baselines for any transgenerational epigenetic inheritance findings.
  3. No detailed physical measurements or samples were taken of their F3 children, which is the generation that may provide transgenerational evidence if the previous generations also have detailed physical baselines.

That study’s researchers drew enough participants (360) such that their statistics package allowed them to impute and assume into existence a LOT of data. But the scientific method constrained them to make factual statements of what the evidence actually showed. They admitted:

“In conclusion, we did not find a transgenerational effect of prenatal famine exposure on the health of grandchildren in this study.”

The current study similarly used the faulty methods 1-3 above to produce results such as:

“We do not have sufficient data concerning the indication for DES in the [F0] grandmother to determine whether adverse pregnancy outcomes in the [F2] third generation might resemble those of their grandmothers.

Fourth [F3] generation effects of prenatal exposures in humans have not been reported.

Zero studies of probably more than 10,000,000 F3 great-grandchildren of DES-exposed women just here in the US?

Who is against funding these studies? Who is afraid of what such studies may find?

It’s possible that these studies would have similar findings to The transgenerational impact of Roundup exposure:

The transgenerational [F3] pathologies observed include prostate disease, obesity, kidney disease, ovarian disease, and parturition (birth) abnormalities.

For the current study:

  • What could be expected from a study design that didn’t include F3 women and men, which is the only generation that didn’t have direct DES exposure?
  • What a nonsensical study design to permit NON-evidence like educational level!

Human studies of possible intergenerational and transgenerational epigenetic inheritance are urgently needed. There will be abundant evidence to discover if researchers will take their fields seriously. “Reproductive and Hormone-Related Outcomes in Women whose Mothers were Exposed in utero to Diethylstilbestrol (DES): A Report from the US National Cancer Institute DES Third Generation Study” (not freely available)

Epigenetic transgenerational inheritance of ovarian disease

This 2018 Washington rodent study investigated ovarian disease in F3 great-granddaughters caused by their F0 great-grandmothers’ exposures to DDT or vinclozolin while pregnant:

“Two of the most prevalent ovarian diseases affecting women’s fertility and health are Primary Ovarian Insufficiency (POI) and Polycystic Ovarian Syndrome (PCOS). POI is characterized by a marked reduction in the primordial follicle pool of oocytes and the induction of menopause prior to age 40. POI currently affects approximately 1% of female population. While genetic causes can be ascribed to a minority of patients, around 90% of POI cases are considered idiopathic, with no apparent genetic link nor known cause.

PCOS is a multi-faceted disease that affects 6-18% of women. It is characterized by infrequent ovulation or anovulation, high androgen levels in the blood, and the presence of multiple persistent ovarian cysts.

For both PCOS and POI other underlying causes such as epigenetic transgenerational inheritance of disease susceptibility have seldom been considered. Epigenetic transgenerational inheritance is defined as “the germline transmission of epigenetic information and phenotypic change across generations in the absence of any continued direct environmental exposure or genetic manipulation.” Epigenetic factors include:

    • DNA methylation,
    • Histone modifications,
    • Expression of noncoding RNA,
    • RNA methylation, and
    • Alterations in chromatin structure.

The majority of transgenerational studies have examined sperm transmission of epigenetic changes due to limitations in oocyte numbers for efficient analysis.

There was no increase in ovarian disease in direct fetal exposed F1 [grandmothers] or germline exposed F2 [mothers] generation vinclozolin or DDT lineage rats compared to controls.

F3 generation ovarian disease

The transgenerational molecular mechanism is distinct and involves the germline (sperm or egg) having an altered epigenome that following fertilization may modify the embryonic stem cells epigenome and transcriptome. This subsequently impacts the epigenetics and transcriptome of all somatic cell types derived from these stem cells.

Therefore, all somatic cells in the transgenerational [F3] animal have altered epigenomes and transcriptomes and those sensitive to this alteration will be susceptible to develop disease. The F3 generation can have disease while the F1 and F2 generations do not, due to this difference in the molecular mechanisms involved.

The epimutations and gene expression differences observed are present in granulosa cells in the late pubertal female rats at 22-24 days of age, which is long before any visible signs of ovarian disease are detectable. This indicates that the underlying factors that can contribute to adult-onset diseases like PCOS and POI appear to be present early in life.

Ancestral exposure to toxicants is a risk factor that must be considered in the molecular etiology of ovarian disease.”

1. The study highlighted a great opportunity for researchers of any disease that frequently has an “idiopathic” diagnosis. It said a lot about research priorities that “around 90% of POI cases are considered idiopathic, with no apparent genetic link nor known cause.”

It isn’t sufficiently explanatory for physicians to continue using categorization terminology from thousands of years ago. Science has progressed enough with measured evidence to discard the “idiopathic” category and express probabilistic understanding of causes.

2. One of this study’s coauthors made a point worth repeating in The imperative of human transgenerational studies: What’s keeping researchers from making a significant difference in their fields with human epigenetic transgenerational inheritance studies?

3. Parts of the study’s Discussion section weren’t supported by its evidence. The study didn’t demonstrate:

  • That “all somatic cells in the transgenerational animal have altered epigenomes and transcriptomes”; and
  • The precise “molecular mechanisms involved” that exactly explain why “the F3 generation can have disease while the F1 and F2 generations do not.” “Environmental Toxicant Induced Epigenetic Transgenerational Inheritance of Ovarian Pathology and Granulosa Cell Epigenome and Transcriptome Alterations: Ancestral Origins of Polycystic Ovarian Syndrome and Primary Ovarian Insuf[f]iency” (not freely available)