Biological invasion is a multi-step process that eventually becomes a major threat to biodiversity. First, a species is intentionally or accidentally transported by human activities, and then introduced at a new location outside its natural range. The introduced species may establish a self-sustaining population, and further disperse to other regions. When it negatively impacts the new ecosystem it has entered, it is called an invasive species. The impact could be ecological, environmental, or economic. For example, when just 24 European rabbits were introduced in Australia for gaming purpose in 1859, they increased to large numbers and spread to the entire continent in less than 50 years. They destroyed the land, crops and also brought a decline to the native biodiversity. The combat to control them in Australia continues till date.

Similarly, many other species had been introduced globally for reasons such as agriculture, farming, ornamental purpose, and recreation. But often these species spillover into the environment, allowing them to invade the ecosystem. One of the major causes of such spillover incidents are also accidental or intentional release of pets, when they eventually turn into a huge menace of destructive nature. Yes, you read it right! Our beloved pets can become a highly invasive species capable of destroying an entire ecosystem. And that could be one of the least troublesome pets such as a cute looking fish.

Let’s see an example from our locality.

Tank-cleaner fishes aka armoured sailfin catfishes from South America are very popular among aquaculture hobbyists in India. Because they do not need high maintenance and also help in keeping the tank clean by feeding on the algal growth. When the pet owner decides not to keep the fish anymore for some reason, they often release the fish into a nearby pond or a lake. There they grow into huge numbers and cause decline of native fishes through competition for food and other resources. In addition to that, their sharp bony plates provide them protection from any potential predator such as birds and other fishes. They are not a favourite delicacy either, and can damage the nets of fishermen when caught. Generally, these fishes are bought when they are just a couple of inches in size, unaware that they can grow more than two feet in length when released into a pond. This kind of monstrous growth can be seen in other fishes as well, like goldfish, many species of catfishes, Alligator gar and Arapaima, some of which can grow up to five feet in length.

Pets turning into invasive species is not only restricted to fishes. Rose-ringed parakeet, Burmese python, Red-eared slider turtle are just a few examples of well-studied invasive species that were initially transported as part of the pet trade. Feral cats and dogs as well are considered among the worst invasive species in the world, responsible for the killing of millions of birds and terrestrial animals annually. Invasive species are also responsible for huge economic losses to the tune of hundreds of crores of rupees every year in India alone. Yet, combating the impact of these invasive species is extremely difficult due to a combination of various reasons such as lack of natural predators, high reproduction and growth rate, their adaptability and resilience to newer conditions etc. And human mediated activities like the intentional release of pets add more fuel to the already raging fire.

Let us shift our focus a little bit towards the elephant in the room. How are we going to curb this menace? Government authorities and some non-governmental organizations have already been working towards tackling invasive species through implementing rules, conducting eradication drives, monitoring illegal pet trades etc. But preventing further introduction of exotic species is possible only through collective action from us, the citizens. It starts with being aware of the problem and the existing rules laid out by the government. If you already own an exotic pet, know about the species through a simple Google search or by consulting a biologist and register them with the government. Obtain proper licenses and permissions to house your pets and to install enclosures. And do register your cats and dogs as well. In case you decide to give away your pet, contact animal shelters or animal welfare organizations for further process.

In contrast, flushing your pet fish or turtle in the toilet or releasing them in the pond, freeing the pet bird, abandoning your pet dog or cat does not only endanger their life, it can also set off a possible biological invasion in future. If you wish to get a pet, discourage wildlife trade by not buying exotic and banned pet species, so that no Marlin needs to desperately seek for his Nemo. Buying exotic pets also promotes the demand and supply feedback which encourages further wildlife trafficking. Displacing any animal from its natural range is not only unethical, but it also disrupts the delicate balance of the ecosystem and poses a huge threat to biodiversity.

And let’s remember that though we call the non-native species as alien species, in reality they are just species that got displaced to alien ecosystems. They are not inherently invasive. Rather, their introduction to non-native regions triggers the process of biological invasion. By now you would have realised that the title of this piece is misleading, and the blame really lies on humans. So, what can we do? Preserving and protecting biodiversity can start at home, sometimes as simple as not flushing your pet tank-cleaner fish down the toilet.

Mitochondria are not new to us. These organelles are found in all eukaryotic cells (cells with membrane bound nuclei), and are the famed powerhouses of these cells. They convert nutrients into usable chemical energy in the form of adenosine triphosphate (ATP). Mitochondria have a very fascinating origin wherein they were thought to have evolved from a free-living bacterium that teamed up with an early eukaryotic cell some billion years ago. This partnership not only gave rise to mitochondria but also provided eukaryotic cells with the ability to efficiently produce energy.

Over time, this association became so integral to cellular function that mitochondria retained their own DNA, separate from the cell’s nuclear DNA. Mitochondrial DNA encodes 13 proteins essential for ATP production, thereby enabling mitochondria to power our cells. But is that all they do? The answer is NO! Recent advancements in science and technology reveal that mitochondria play many roles in keeping our bodies healthy, particularly through their involvement in regulating the immune system.

Mitochondria and Immunity

Immune system is the body’s defense force that protects us from various infections and diseases caused by bacteria, viruses and other pathogens. It works through two major responses.

One is the innate immune response. It is the body’s first-line defense against viruses and bacteria. Cells detect unique markers on these pathogens such as proteins, carbohydrates and nucleic acids, and initiate secretion of chemicals like chemokines and cytokines. Mitochondria play a crucial role in this process. For instance, during viral infection mitochondria activate the immune response with the help of protein called MAVS (Mitochondria Anti-Viral Signaling) upon detecting the presence of virus in the cell. Through this protein, it relays the danger signals to the neighboring cells as well as protects the cell from the pathogens by producing a group of cytokines called interferons.

Additionally, mitochondria release their own DNA and proteins into the cell when damaged, which can trigger the immune response. While mitochondrial DNA and proteins are not inherently foreign to the cell, their presence in the cytoplasm due to mitochondrial damage or stress is interpreted as a threat, prompting an immune response.

Mitochondria also help in the adaptive immune response, the second line of defense of our bodies. This response takes longer to kick in but is more precise. It not only recognizes but also remembers specific pathogens to fight them more effectively in case of future infections using special immune cells. Mitochondria are essential in the formation and activation of these specialized cells. They provide the necessary environment for immune cells to function properly. Studiessuggest that defective mitochondria in immune cells can lead to a compromised immune response, emphasizing the critical role mitochondria play in immunity.

Immune systems need to act rapidly and constantly to keep us healthy. And mitochondria enable this through keeping a tight check on their own quality. It is not a mean task for these highly dynamic organelles.

Quality Control of Mitochondria

Contrary to the age old static ovoid structure illustrated in many books, mitochondria constantly undergo cycles of splitting to form new ones and fusing with other mitochondria. Splitting helps in regulating their numbers in the cell, and distribute them across the cell according to the local needs inside a cell. Fusion helps in supplementing defective parts of a mitochondrion with effective ones from other mitochondria, adding to its function and life. When a mitochondrion is too damaged to be repaired, the cell breaks it down and recycles its parts.

If mitochondria are not properly maintained, it can lead to many problems for cells. Decreased energy production is only one of them. If the structural integrity of mitochondria is compromised, it leads to leakage of reactive oxygen species, a rather harmful by-product of energy production in mitochondria, into the cells. These eventually kill cells and contribute to various diseases like neurodegenerative diseases, cardiac diseases and cancer, in addition to the direct impact on immune responses.

Mitochondria – A target for microbes

Given that mitochondria are fundamental to regulating immune responses, it is not surprising that many bacteria and viruses target them to evade immune defenses and establish infection. Each pathogen manipulates mitochondria in unique ways to ensure its survival and propagation within the cell.

For example, viruses like the Dengue virus manipulates splitting of mitochondria by cleaving the protein that facilitates the process, while others like Hepatitis C Virus and Japanese Encephalitis Virus interfere with mitochondrial fusion and promotes excessive splitting and recycling process. This disturbs the dynamic balance of mitochondria to evade antiviral responses and persist in the cell. This disruption alters the distribution and aggregation of MAVS, leading to impaired secretion of interferons, which are crucial for clearing the virus.

While these are only few examples, scientists are increasingly focusing on understanding the intricate interplay between mitochondria and immunity. These fascinating organelles have thus become the powerful pharmacological target to fight infections. Numerous clinical trials are currently evaluating new experimental drugs designed to target mitochondria.

All of these newer understanding of mitochondria’s role in our health bring optimism for translating pre-clinical discoveries into clinical treatments. But the journey from discovery to clinical approval is way too long! In the meantime, one can improve mitochondrial health as a potential tool to enhance immunity. Eating a balanced diet, exercising regularly, getting enough sleep, managing stress, avoiding toxins through smoking and by staying hydrated can support and improve the health of your mitochondria and the cell as a whole. Healthy mitochondria mean more energy, better overall health and a stronger ability to fight off infections!

It was a typical Sunday. My mother and I were engaged in our usual conversations, discussing family matters to office gossip, and making plans for the upcoming week. My mother had recently heard of genetic tests to predict diseases, and thought of bringing that up. Sooner than we knew, our conversation had taken an unexpected educational turn.

I am the first biologist in a family of chefs, teachers, and businessmen. I am currently pursuing a PhD in human genetics and am often turned to for advice by my family members for anything biology or medicine. My mother is a teacher, and questions everything. She has a medical condition known as ankylosing spondylitis, which is an autoimmune disorder. In this condition, the immune system of the body starts attacking its own cells present in the spine. Despite being in severe chronic pain, she is a warrior and never gives up, she works, goes for yoga and loves to dance in the disco. But she also prays every day that her children should never get this disease.

Ankylosing spondylitis has been associated with a mutation in the HLA-B27 gene, meaning that the disease has genetic origins. My mother knows that if the gene has already been passed to us, prayers may not be able to fix that! So she wanted to know if the genetic tests can be useful to us.

Direct-to-consumer genetic testing (DTC GT) has gained a lot of popularity over the past few years. The idea that we can order a genetic test for ourselves online, without even having a doctor’s prescription is quite exciting. Quickly, we were deep into the details of what such genetic tests promise and can deliver. Mom asked if knowing about the genetic information will help us prevent the disease. The question was simple; however, I realised the answer was rather complex.

Our genetic data is like a manual to our body and just like the ones for IKEA furniture, it might not always be easy to interpret. Some genetic mutations alter protein structures, and hence there is no scope for preventing it. Sickle Cell disease, for instance, is a genetic disorder that occurs due to a specific mutation in the haemoglobin gene. This mutation causes the red blood cells’ haemoglobin to clump together, which changes the cells’ shape from round to sickle-like. This mutation is certain to cause the disease in someone having both diseased copies of the gene and cannot be prevented, as of today, despite having the knowledge that the individual has the mutation.

Some genetic mutations can cause a protein to be dysfunctional, produced less, or ineffective in processing a substance in the body. Knowing about such a condition can help an individual receive appropriate treatment or take preventive measures. For example, a genetic test can indicate whether an individual is at risk of developing lactose intolerance. Lactose intolerance occurs when the body cannot digest lactose, a sugar found in most dairy products, due to insufficient production of an enzyme called lactase. Although most infants are born with the ability to produce lactase, its production decreases with age. People who produce too little lactase may experience bloating and other stomach issues after consuming lactose-containing products. The solution to this problem is simple: avoid dairy products that contain lactose.

On the other hand, several illnesses, such as ankylosing spondylitis, type 2 diabetes and certain cancers, are categorized as complex diseases. This means that they can arise due to multiple genes and environmental factors. Therefore, even if a person possesses the genes for the disease, they may not necessarily develop it if they take preventive measures. In such cases, it may be beneficial to determine your genetic predisposition to these diseases.

Having said this, it’s important to clarify that the genetic risk for complex diseases, as the name suggests, are not easy to find out. The risk of getting a condition like diabetes has been associated with several hundreds of genes. An individual’s risk of diabetes can be assessed by summing up the effect of both risk and protective mutations, this metric is referred to as a polygenic risk score. To find these genes, enormous studies involving participation of several lakhs of people are required; most of these have been conducted in European populations. The genetic risk scores derived from European populations are capable of predicting diseases in different ancestries only to some extent. Their accuracy reduces depending on how genetically diverse the population is from the Europeans.

In a study of more than 1000 Asian genomes, researchers found that 23% of the protein-affecting genetic variants they identified were previously unreported in existing genomic databases with majority European and Non-Asian representation. Hence, a genetic score that may predict the risk of a disease in Europeans may not necessarily be accurate in Indians. To date, information on other populations such as Asians and Africans remain scarce, and hence, results provided from DTC GT reports must be taken with caution, if you are an Indian. It is crucial to inquire with the DTC GT company you choose about the origin of their data, and if their conclusions are drawn from the population you identify with. By doing so, you can gain a better understanding of the significance of the information provided in their report.

Phew! My mom sighed and stopped me mid-way indicating that she got the gist and instantly popped the next question. “So”, she said, “I have little control over some genetic disorders and may not be able stop the disease from occurring in myself. However, could I have prevented passing the diseased genes to my children? Also, now since the damage might already have been done, can I know what genetic risks I have passed on to my children?”

I continued to explain – If you have taken a genetic test and discovered that you are genetically predisposed to a particular disease, it is possible to have your children tested to determine if they also carry the genetic risk. Some disorders, such as sickle cell disease and thalassemia, manifest when an individual acquires faulty genes from both parents. If you possess only one copy of the faulty gene, you will not develop the disease and may not be aware that you are a carrier. However, if your partner also carries the same faulty gene, there is a 1 in 4 chance that your child will inherit both copies, resulting in the disease. In such cases, it is advisable to determine if you and your partner carry the risk mutations before having children to prevent the possibility of having a child with a severe, sometimes lethal disorder. However, similar preventative testing before pregnancy for complex diseases that are caused by a combination of genetic and environmental factors is not yet feasible.

Curious about the experiences of others who had undergone genetic testing, she started pondering what they had gained from it. I took to the internet and discovered a variety of responses. Many individuals who have discovered that they are at an increased genetic risk of developing a particular disease have adopted preventive measures, such as lifestyle changes, to reduce their risk. Others become anxious when they learn that they have a high risk of developing a disorder like breast cancer. Some people are also dissatisfied with the language used in genetic testing reports, which often include terms like probabilities and relative risks, and struggle with interpreting the results they receive. Clearly, there is a still a lot to understand how these tests can become more useful and user-friendly.

Nevertheless, according to an article on the American Medical Association website, about 100 million people had been estimated to have taken a DTC genetic test in 2021. So, the popularity of these tests is definitely on a rise.

“How safe would it be to hand over the information of your genes to these companies, could they misuse it?,” my mom asked with some scepticism. Some digging into the policy documentation of various companies told me that each DTC GT company has its own privacy policy that clearly specifies and obtains consent regarding the data the client is willing to share. Hence if opting for such a service, it is critical to thoroughly read and understand the policy before enrolling in the service. Also, it’s important to take note that this field is still in its nascent stages and these companies may not be well regulated by medical agencies in India.

With some trepidation, I asked her, “Mom, now that you have a better understanding of these tests, do you think you would consider getting one?” In response, she delighted me by singing her all-time favourite song –
“Qué será, será
Whatever will be, will be
The future’s not ours to see
Qué será, será
What will be, will be”