Genetic Genealogy and DNA Help Solve 34-Year Old Murder Case

An article by The San Diego Union-Tribune discussed the murder of Diane Dahn, a woman who was 29 when she was brutally stabbed in 1988. She was left for dead in her apartment, and while investigators kept investigating the case for decades to come, it was not until recently with new genetic techniques that a suspect was able to be determined. 

Before genetic genealogy came into play for Dahn's case, DNA techniques were used as early as the 2000s. There were several pieces of DNA that were able to be used from Dahn's fingernails as well as a hair that was found in her hand, but when entered into the national databases, there were no matches. It was not until May of 2020 that genetics took over and really helped aid the investigation.

Genetic genealogy uses atDNA, also known as autosomal DNA in order to identify how closely related certain individuals are to each other. This type of DNA is inherited in all individuals and can be seen in both males and females. While the single nucleotide polymorphisms are harder to detect using forensic samples, technology is advanced enough to obtain information from small or degraded samples. The longer a segment is shared between two individuals, the more closely related they are. This helps establish family trees and helps piece together these kinds of cold cases.

Through the use of several genealogy websites, investigators were able to identify relatives of the suspect in order to find possible matches. These websites allowed law enforcement to see open DNA profiles in order to biologically look at the DNA and make certain matches for relatives. Family trees, or pedigrees, were created based on the matches found through the websites and 1,300 relatives and 9 pedigrees were able to be created based on the results of the unknown suspect. This led to finding the suspect's children, and when a paternity test was done, they found the suspect: Warren Robertson, a man who lived in the same apartment complex as Dahn, but had died in a fire in 1999.

Based on the success of this case, as well as 5 others San Diego have solved, genetic genealogy is on the rise and provides good results in order to help locate a suspect or provide more information based on DNA profiles found at a crime scene. I think while it is a tedious and difficult process, the success rate of genetic genealogy and the information being discovered is amazing and helps in the field of forensic science. Forensic biology is on the rise as DNA and its advancements provide helpful information. I believe these biological techniques are here to stay and aid in law enforcement investigations which is a win-win in terms of science and criminal justice.

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Progress is Being Made on Finding a Cure to Type 1 Diabetes

 

    An article from U.S. News says that a 64-year-old man named Brian Shelton is one of the first type 1 diabetes patients to receive a transplant of experimental pancreatic stem cells which enables him to make insulin on his own. This treatment is not exactly perfect, as Shelton has to take immune suppressing drugs to prevent his body from rejecting the transplanted cells.

    This treatment was created by Vertex Pharmaceuticals can help people with type 1 diabetes whose condition has become life-threatening or who have developed a resistance to insulin or other diabetes medications. The next step researchers are looking to take with this treatment is trying it on other patients, they are looking to test the cure on 17 other patients and to observe the effectiveness and safety of the treatment for both long and short-term.

    The end goal for researchers is to create a treatment with pancreatic stem cells that requires less or no immune suppression at all. In type 1 diabetes patients, the immune system is attacking and destroying beta cells in the pancreas that produce insulin, and this response would continue on the transplanted pancreatic stem cells without immune suppression. The body will also identify the stem cells as foreign and attack and destroy them as well if the immune system was not suppressed. 

    Researchers are looking at different methods to combat this challenge that involves covering the stem cells in a capsule that would protect them from the immune system. The capsule was designed to allow oxygen and nutrients into the cells but prevent immune cells from entering and attacking the cells. The capsule has been shown to be relatively ineffective due to the fact that the insulin produced was too little to make a change for the patient. Companies are not abandoning this method quiet yet and are still working and testing this method.

    Another method has also been looked into, and it involves gene editing that would allow the transplanted cells to be undetectable by the immune system. This method could be a great solution for the negative immune response because it will protect the cells while also still allowing the cells to produce insulin.

    Researchers do admit that it will be a long time before this treatment will be widely available to the public, and that lots of testing and research is defiantly needed a on the matter.

    As some who has a family member with type 2 diabetes, and know many other people with type 1 diabetes, I do understand some of the struggles of having diabetes and the toll it takes on one's body. I also understand how it can be a struggle and very scary not being able to control your blood sugar and constantly needing to monitor it. This treatment shows a lot of prospects and helps to give hope of a better life to those who are suffering from type 1 diabetes. 

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What Is Type 1 Diabetes? | CDC

Scientists Discover Genes that Make Your Fingerprints

 

    According to an article from U.S. News, scientists have discovered that human fingerprint patterns are linked with genes responsible for limb growth during fetal development. After looking at DNA from over 23,000 individuals, scientists found 43 genomic regions that are associated with fingerprint patterns. The region with the most influence is known as EVI1, and it plays a critical role in embryotic limb development. To test their findings, they restricted the expression of EVI1 in mice, and this resulted in the mice having abnormal patterns on their digits. 

   The article also talked about how previous studies had suggested that EVI1 is linked to leukemia risks, and that it was observed that people who were more susceptible to leukemia had more whorl patterns on their fingers. The researchers all agree that more investigation is needed to truly understand the relationship between fingerprints, genes, and diseases. 

    I found this study very fascinating because it had never occurred to me that fingerprints could be related to genetics. I also did not know that some fingerprint patterns are being associated with diseases like leukemia. I believe this will expand the use of the fingerprint long past simply identifying a person but being able to determine a better profile of a person based on their fingerprint patters.

    Related Article

Fingerprints and Science – Fingerprinting in the Modern World (rutgers.edu)

Transcriptome Analysis of Sponge Response to Wounding Revealed Putative Orthologs of Cancer-Related Human Genes

 

        The wounding of sponges allows researchers to understand the fundamental processes that control how healthy tissues are maintained in response to injury. The response was remarkably similar to the way cancer works.
        This study focused on the Aplysina aerophoba transcriptomic response to wounding by grazers and mechanical injury. Their response was evaluated by analyzing the differential gene expression in RNA sequence data. According to Wu et al., “In the set of proteins codified by sponge genes responding to mechanical damage, [they] identified putative orthologs of human proteins involved in G-protein coupled signaling pathway, ubiquitination, and components of the MAP kinase signaling transduction pathway”. These genes are associated with cell adhesion, proliferation, and differentiation. When these behaviors become unregulated, it results in a tumor.
        Putative orthologs of cancer-related human genes allow researchers to assess the mechanisms of evolution through the lens of genes with the same biological function in other animal phyla. This area of study seems promising because, unlike other organisms involved with cancer research due to their regenerative capabilities, such as planarians, sponges are the first animal lineage to appear on Earth.

What To Read Next: A sponge makes a molecule called manzamine A which stops the growth of cervical cancer cells.

Possible Correlation Between Maternal Depression and Gene Expression in Fetuses

        In an article from The Scientist, Chloe Tenn discusses how depression may be correlated with epigenetic changes to the placenta in pregnant women. The connection of maternal depression and stress to the developing fetus has not yet been proven, but is currently under investigation. The National Institutes of Health (NIH) monitored over 300 women during their pregnancies between 2009 and 2013. They used surveys to assess their mental health at six intervals during their pregnancies and compared them to placental tissue samples they collected after delivery. 

     After comparing the data NIH genetic epidemiologists discovered that in their sample of women maternal depression was linked with 16 methylation sites, while stress was linked to another two sites. DNA methylation regulates gene expression, and typically acts to repress gene transcription. Two of the sites that were found to be linked with depression are associated with changes in the expression of ADAM23 and CTDP1 genes. These genes affect neurodevelopment and psychiatric conditions such as schizophrenia and bipolar disorder.
       

    Opinion: The sample size of the experiment was quite small, but the reasoning seems sound. Much more research will be needed to come to a conclusion, but depression and stress have an impact on hormones which could lead to epigenetic consequences for children still in utero. 

Capuchin Monkeys Experience Test Anxiety, Too

 

   A recent article in Science Daily explains that when capuchin monkeys were administered a computerized matching test in which the difference in difficultly was removed, some of the monkeys struggled under pressure. These monkeys, located at Georgia State's Language Research Center, were given rewards when harder tests were passed, and put in timeout when they answered incorrectly, meanwhile, other trials were conducted using difficultly levels the monkeys were familiar with.

    The researchers had discovered that during the monkeys' performances, there was a significant level of cortisol, a hormone in our bodies that responds to stress. This evidence could possibly be used to create a better understanding of the evolution of cognition in humans, and now other species.

For more information on this study, click here.

Assessment of Genetic Variation and Species Distribution Modeling Used to Formulate a Conservation Plan for the Keystone Species Astacus astacus

    Anthropogenic impacts have decreased the genetic diversity of Astacus astacus, the noble crayfish. It is expected that only 13 percent of the crayfish will survive, excluding the most genetically diverse populations. 
    Mitochondrial and nuclear DNA variations among crayfish were assessed to determine genetic diversity across multiple populations. The mitochondrial DNA revealed that six genetic lineages exist. Using the nuclear DNA, 175 alleles were observed across the 15 microsatellite loci, with an average of 12 alleles per locus. 
    Species distribution modeling showed the current and future susceptibility of habitats to climate change. The information collected was then used to predict invasive species that cause disease in the indigenous populations' future migration patterns. The results also showed that many crayfish populations were isolated from gene flow.
     The conservation plan recommended assisted migration and repopulation to protect this keystone species. By creating a population with multiple genetic lineages and ensuring that the new locations are less susceptible to invasive species, assisted migration and repopulation have a higher chance of success.
    Genetic diversity is essential for increasing the adaptive capability of a population. A disease that affects one individual is likely to have the same effect on individuals that share similar genetic information. As such, crayfish should be prioritized for protection since the indigenous crayfish population is especially vulnerable due to its lack of genetic diversity. 
    There is still diversity across the different populations which allows for recovery; however, introducing species from one population to another should be done with caution. Previous studies have shown that genetic erosion can occur when introducing domesticated organisms to wild populations. Although, in this case, it would be the introduction of one wild population to another, the same principle still applies since genetic variation exists. It is vital to consider every outcome and test potential impacts before implementing conservation efforts since it is harder to reverse actions than to take them in the first place.

What to read next: Multiple drivers of decline in the global status of freshwater crayfish (Decapoda: Astacidea). 

Preference for Black Coffee and Dark Chocolate has Been Linked to Genetics

   An article from U.S. News talks about how scientists have discovered that people who like black coffee likely inherited this preference from someone in their family. Scientists found that black coffee drinkers' have a genetic variation that allow them to metabolize caffeine much faster than a regular person. Because they metabolize caffeine faster, the stimulating effect that caffeine has wears off much faster as well, and this results in them drinking more or stronger coffee. Scientists believe that these people begin to association the bitter taste of coffee with mental alertness and the stimulation caffeine gives them, and they tend to have a preference for other bitter foods like dark chocolate.

    As someone who does not particularly like coffee or drink it, I find this very interesting especially since I could never understand why some people find black coffee so appealing. It is amazing to learn that a genetic variation that changes the way someone metabolizes caffeine can create this learned behavior and preference for bitter tasting foods.

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