2019 was a big year for genomics research. Topics like pharmacogenomics, mental health, population studies and multiomics dominated the discussion of most genetic conferences. In this blog, we are highlighting a few genomics research studies from 2019 that we found interesting.

1. Saliva micro-RNA differentiates children with Autism from peers

Many scientists are testing the utility of salivary micro-RNAs with various diseases. Quadrant Biosciences specializes in research of many diseases, including children with Autism. ^[1]

In March 2019, Hicks et al. published their research on saliva microRNA patterns among children with autism spectrum disorder (ASD) and how salivary microRNA can be used for differentiating children with ASD from peers with typical development (TD) and non-autism development delay (DD). ^[1]

“Since the multifactorial genetic and environmental risk factors that have been identified in [autism spectrum disorder], it is possible that at least 1 epigenetic mechanism might play a role in ASD pathogenesis. Among these potential mechanisms are microRNA (miRNAs).”^[1]

Their study enrolled 443 children between the ages of 2 to 6 years who were in the early stages of diagnosis of Autism. They collected saliva samples from this cohort using an RNA saliva collection kit prototype from DNA Genotek.^[1]

(Working with RNA and interested in more information about RNA from saliva? email us at info@dnagenotek.com.)

miRNA and autism: highlighted study results

• 14 salivary miRNAs were identified with varying levels in children with autism and their peers with TD and DD.
  • 4 miRNAs were distinguished in children with autism
  • A subset of miRNAs were associated with measures of adaptive and autistic behaviours
• Salivary miRNA differs in children with autism compared to healthy control participants.
• They found 8 miRNAs associated with social affect and 10 miRNAs associated with restricted/repetitive behaviour in children with autism^[1]

The study provides evidence that salivary miRNA could be used to differentiate children with autism from their peers. Salivary miRNA is correlated with autistic behaviours and target pathways that are involved in autism pathogenesis. ^[1]

Related content: The SPARK project – Fueling the fire on autism research ; Could microRNA from saliva be a predictor of concussion symptoms in children?

2. Genes and PTSD in U.S. service members deployed to Iraq and Afghanistan

“Posttraumatic stress disorder (PTSD) is a chronic and debilitating condition with a prevalence of more than 7% in the US population and 12% in the military.”^[2]

Through previous studies involving families and twins, there has been an established genetic component in the development of PTSD. Lifetime trauma incidences are the most commonly known contributors of PTSD, however, children whose parents have PTSD have higher rates of development than the general population.^[2]

According to Zhang et al. at the Uniformed Services University of Health Science in Bethesda, MD, genetic influences account for 1/3 of the risk of developing PTSD. The range of developing PTSD from a lifetime trauma in the general population is between 40-90%.

In 2004, Binder et al. discovered that those in the general population carrying the FKBP gene have a higher chance of developing adult PTSD if they experience childhood trauma.^[3]

Zhang et al. published a paper on Jan 3rd 2020, studying the FKBP5 gene with a high-risk PTSD population: US service members deployed to Iraq and Afghanistan. Even though their paper was published in 2020, we decided to include it in this list since the paper itself was submitted in August 2019. ^[2]

FKPB5 a risk factor for PTSD

Dr. Ursano and his team collected saliva using Oragene·Discover from 3890 US service members ages 18 to 62 years, who served during the combat operations in Afghanistan and/or Iraq from 2008-2016.^[2]

• Probable PTSD patients were more likely to carry the 4 single nucleotide polymorphisms (SNPs) markers covering the FKPB5 gene
• The data of combat exposure and trauma history suggest that gene-environment interactions may play a role in PTSD development in the US military population.
  • Service members with different FKBP5 genotypes are affected differently by exposure to the same environmental factors – meaning the gene-environment interactions can result in different phenotypes.
  • The AGCC haplotype carriers have the highest risks of PTSD development.^[2]

Related content: Genetics and post traumatic stress disorder; Saliva DNA enables pharmacogenetic testing for psychiatric medication

3. Genetics of complex behaviour traits in dogs and how they relate to humans

Man’s best friend is as genetically complex as we are. According to scientists like Boyko et al., dogs are a very useful animal model for identifying genetic basis of various phenotypes because of their favourable genetic structure. ^[4] Complex behaviours in canines are known to have a genetic component which can be useful when gaining insights into genetic mechanisms underlying conditions that are relevant in humans, such as obsessive compulsive disorders (OCD). ^[5]

Friedrich et al. from the University of Edinburgh, published a study in May 2019 focusing on the genetic structure of complex behaviours traits in German Shepherds and how some of these genes can be linked to humans. They extracted DNA from 768 German Shepherd dogs from saliva using PERFORMAgene (UK cohort) and blood (Swedish cohort). They analysed the influence of genetic factors on behaviour traits.

They found genes that are associated with specific behaviour traits from German Shepherds that also are affiliated with humans. Below are some examples of their findings:^[5]

"Understanding the genetics of dog behaviour and the interaction with non-genetic factors can give general insights into animal and human behaviour and is relevant for animal welfare.” ^[5]

This study is just one example of the value canine studies have as a resource for studying the genetics of behavioural characteristics.^[5]

(If you are interested in learning more about collecting DNA from canines or other animals, click here to request free samples of PERFORMAgene saliva collection kits or email us at info@dnagenotek.com for more information).

Related content: Podcast: Multiomics methods investigate aging process in man's best friend

4. Thinness is a heritable genetic trait just like obesity

Have you ever wondered why some people are particularly susceptible to obesity and others to thinness? Approximately 40-70% of the variation in body weight can be attributed to heritable factors. Studies in the past have mostly focused on the genetic characteristics of the body mass index (BMI) of obesity, however, little is known about the genetic characteristics of thinness. ^[1]

There have been only a few studies that show thinness to be a trait that is at least as stable and heritable as obesity.

In January 2019, Riveros-McKay F et al.  from the University of Bristol, published their research on the genetic architecture of human thinness compared to severe obesity. To-date, they are the newest and largest genome-wide association study GWAS focused on healthy thinness in contrast with severe early-onset obesity. 

“We explored whether the genetic loci influencing thinness are the same as those influencing obesity.”^[6]

Thinness vs obesity: how do they compare genetically?

Riveros-McKay et al.  genotyped data for 1,622 thin and healthy individuals (using saliva samples via Oragene·DNA), 1,985 severe childhood onset obesity cases (using whole-blood samples), and 10,433 population-based individuals used as controls (samples taken from the UK Bio-bank).^[6]

• Genotyping results show that healthy thinness is a heritable trait just like obesity
• Persistent healthy thinness and severe obesity are negatively correlated and share a number of genetic risk loci (likely due to the degree of extremeness of the two cohorts)
  • One gene found to be shared is CEP120 which has been previously associated in other studies with height and weight circumference^[6]

Related content: Obesity, Hypertension and Cardiovascular Risk in Italian Youth; Losing weight – do your genes play a role?

What will genomics research look like in 2020?

Let us know in the comments section about what research topics you found interesting from 2019 and what research trends you think will dominate 2020.

To request free samples of DNA or RNA collection kits click below or please email us at info@dnagenotek.com.

References

[1] Riveros-McKay F et al. Genetic architecture of human thinness compared to severe obesity. PLOS Genet. 15(1):e1007603.

[2]Zhang L et al. Genetic associations of FKBP5 with PTSD in US service members deployed to Iraq and Afghanistan. J Psych Research. 122: 48-53 (2020).

[3] Binder EB et al. Polymorphisms in FKBP5 are associated with increased recurrence of depressive episodes and rapid response to antidepressive episodes and rapid response to antidepressive treatment. Nat Genet. 36(12):1319-1325 (2004).

[4] Boyko AR et al. The domestic dog: man’s best friend in the genomic era. Genome Biol. 12:216 (2011).

[5] Friedrich J et al. Genetic complex behaviour traits in German Shepherd dogs. Heredity. 123:746-758 (2019).

[6] Riveros-McKay F et al. Genetic architecture of human thinness compared to severe obesity. PLOS Genet. 15(1):e1007603.