Science Current Events | Science News | Brightsurf.com
 

Monogamy and the Immune System

August 31, 2012

In the foothills of the Santa Cruz Mountains two closely related species of mice share a habitat and a genetic lineage, but have very different social lives. The California mouse (Peromyscus californicus) is characterized by a lifetime of monogamy; the deer mouse (Peromyscus maniculatus) is sexually promiscuous.

Researchers at the University of California Berkeley recently showed how these differences in sexual behavior impact the bacteria hosted by each species as well as the diversity of the genes that control immunity. The results were published in the May 2012 edition of PLoS One.

Monogamy is a fairly rare trait in mammals, possessed by only five percent of species. Rarely do two related, but socially distinguishable, species live side-by-side. This makes these two species of mice interesting subjects for Matthew MacManes, a National Institutes of Health-sponsored post-doctoral fellow at UC Berkeley.

Through a series of analyses, MacManes and researchers from the Lacey Lab examined the differences between these two species on the microscopic and molecular levels. They discovered that the lifestyles of the two mice had a direct impact on the bacterial communities that reside within the female reproductive tract. Furthermore, these differences correlate with enhanced diversifying selection on genes related to immunity against bacterial diseases.

Bacteria live on every part of our bodies and have distinctive ecologies. The first step of MacManes project involved testing the bacterial communities that resided in the vaginas of both species of mice - the most relevant area for a study about monogamous and promiscuous mating systems.

Next, MacManes performed a genetic analysis on the variety of DNA present, revealing hundreds of different types of bacteria present in each species. He found that the promiscuous deer mouse had twice the bacterial diversity as the monogamous California mouse. Since many bacteria cause sexually transmitted infections (like chlamydia or gonorrhea), he used the diversity of bacteria as a proxy for risk of disease. Results of the study were published in Naturwissenschaften in October 2011.

But this wasn't the end of the exploration.

"The obvious next question was, does the bacterial diversity in the promiscuous mice translate into something about the immune system, or how the immune system functions?" MacManes asked.

MacManes hypothesized that selective pressures caused by generation after generation of bacterial warfare had fortified the genomes of the promiscuous deer mouse against the array of bacteria it hosts.

To find out, he sequenced genes related to immune function of the two mice species and compared each species' versions of one important immunity gene, MHC-DQa. Some forms of genes (alleles) are better at recognizing different pathogens than others. If an individual has only a single common allele, it may only recognize a limited set of bacterial pathogens. In contrast, if an individual has two different alleles it may recognize a more diverse set of bacterial pathogens, and thus be more protected against infection.

Based on a comparison of the two species' genotypes he confirmed that the promiscuous mice had much more diversity in the genes related to their immune system.

"The promiscuous mice, by virtue of their sexual system, are in contact with more individuals and are exposed to a lot more bacteria," MacManes said. "They need a more robust immune system to fend off all of the bugs that they're exposed to."

The results, published in PLoS One, match findings in humans and other species with differential mating habits. They show that differences in social behavior can lead to changes in the selection pressures and gene-level evolutionary changes in a species.

Motivated by this result, MacManes began work on a project that looked to understand the genetics of a far more complex behavior-whether to stay at home with relatives, or to disperse to a new burrow.

Scientists have been sequencing and exploring the genome for more than a decade. For much of this time, studies have been limited to the most common and well-known species: humans, lab-mice, and fruit flies. But in recent years, as the cost of sequencing has dropped and the methods of exploring genomic information have improved, researchers have begun to analyze other less traditional organisms.

MacManes project was one of the first studies to use next-generation gene sequencing and high performance computers to assess the influence of behavior on genes in a non-model species.

"This is a field that people have always been interested in, but the tools hadn't existed yet for people to really understand how complex the mechanisms were," MacManes said.

Next-generation sequencing determines the order of the nucleotide bases in a molecule of DNA by breaking the double helix into short fragments and rapidly analyzing thousands of chunks at a time. Once hundreds of millions of genetic snippets have been read out by a DNA sequencer, they must be assembled into a single genome, or mapped to a reference genome, and compared to other genetic sequences to be useful.

"The sequencing is something that you can do in any molecular biology lab-that's easy," MacManes said. "But when you try to do an analysis of the data, you get back something like several billion base pairs of data. How to actually analyze the data is the real issue."

As a National Science Foundation (NSF) graduate research fellow, MacManes learned that researchers could access NSF supercomputers through the Extreme Science and Engineering Discovery Environment (XSEDE) to analyze datasets too big for their university laboratory clusters. Once he had his sequences, MacManes turned to the Texas Advanced Computing Center (TACC) at The University of Texas at Austin, a lead partner in XSEDE and home to the Ranger supercomputer.

"When we first started using Ranger, it was a breakthrough moment for us," he said. "We had the data set, but we didn't have any way to do anything with it. Ranger was really our first real chance at analyzing this data. "

The alignment and analysis that MacManes accomplished on Ranger in a few weeks would have taken years with his local resources. It organized the data so MacManes could find insights about the relationship between genes and behavior.

"The ability to isolate and compare genetic differences related to social behavior using advanced computing is a fascinating application of emerging technologies," said Jennifer Verodolin, a researcher specializing in social rodents at the National Evolutionary Synthesis Center in Durham, North Carolina. "We often see individual and population-level social and mating differences within the same species. While ecological factors are linked to this variation, these sophisticated new tools will now allow us to see the genetic signature of how natural selection has shaped behavior."

Mating systems, and social systems more broadly, are important to basic evolutionary biology, MacManes asserted. "The things an animal does, the way it behaves, and who it interacts with, are important to natural selection. These factors can cause immunogenes to evolve at a much faster rate, or slower in the case of monogamous mice. That connection is important and probably under-recognized."

Monogamy and promiscuity are only one of a variety of social behaviors that are thought to influence gene expression. MacManes' current research involves analyzing gene expression in the hippocampus brain region of tuco tucos (a sort of South American gopher) who live together in social groups and others who live independently. He is hoping to find what differentiates the social animals from the loners and what impact this change in their behavior has on their genetic profile.

"Now that we have these new sequencing technologies, people are going to be really interested in looking at the mechanisms that underlie these behaviors," MacManes said. "How might genes control what we do, and how we behave? We're going to see an explosion in these studies where people start to understand the very basic genetic mechanism for all sorts of behaviors that we know are out there."

Texas Advanced Computing Center


Related Immune System Current Events and Immune System News Articles


Why malnutrition is an immune disorder
Malnourished children are most likely to die from common infections, not starvation. New experimental evidence, reviewed May 26 in Trends in Immunology, indicates that even with a healthy diet, defects in immune system function from birth could contribute to a malnourished state throughout life.

Slime mold reveals clues to immune cells' directional abilities
How white blood cells in our immune systems home in on and engulf bacterial invaders--like humans following the scent of oven-fresh pizza--has long been a mystery to scientists.

Migration back to Africa took place during the Paleolithic
The Palaeogenomics study conducted by the Human Evolutionary Biology group of the Faculty of Science and Technology, led by Concepción de la Rua, in collaboration with researchers in Sweden, the Netherlands and Romania, has made it possible to retrieve the complete sequence of the mitogenome of the Pestera Muierii woman(PM1)using two teeth.

Researchers identify immune genes tied to common, deadly brain cancer
Researchers have identified a group of immune system genes that may play a role in how long people can live after developing a common type of brain cancer called glioblastoma multiforme, a tumor of the glial cells in the brain.

Can Alzheimer's disease-associated peptide fight bacterial infection?
Amyloid-ß is a sticky peptide notorious for forming destructive plaques in the brains of Alzheimer's disease patients, but a new study suggests that it may also serve a protective function as an antimicrobial peptide.

Human amyloid-beta acts as natural antibiotic in the brains of animal models
A new study from Massachusetts General Hospital (MGH) investigators provides additional evidence that amyloid-beta protein - which is deposited in the form of beta-amyloid plaques in the brains of patients with Alzheimer's disease - is a normal part of the innate immune system, the body's first-line defense against infection.

Antiretroviral therapy may not be enough to reduce HIV-associated arterial inflammation
Initiating antiretroviral therapy (ART) soon after diagnosis of an HIV infection did not prevent the progression of significant arterial inflammation in a small group of previously untreated patients.

Is aging inevitable? Not necessarily for sea urchins
Sea urchins are remarkable organisms. They can quickly regrow damaged spines and feet.

Researchers make a key discovery in how malaria evades the immune system
The malaria parasite Plasmodium falciparum hijacks an immune system process to invade red blood cells, according to a study led by researchers at Penn State College of Medicine. Understanding how malaria invades the cells could lead to a more effective vaccine.

Study reveals protein that dials immune responses up and down
Research led by scientists at the Sanford Burnham Prebys Medical Discovery Institute (SBP) has identified a new regulator of immune responses.
More Immune System Current Events and Immune System News Articles

The Immune System Recovery Plan: A Doctor's 4-Step Program to Treat Autoimmune Disease

The Immune System Recovery Plan: A Doctor's 4-Step Program to Treat Autoimmune Disease
by Susan Blum (Author), Mark Hyman (Foreword), Michele Bender (Foreword)


One of the most sought-after experts in the field of functional medicine shares her proven four-step program to treat, reverse, and prevent autoimmune conditions and repair your immune system.

• Are you constantly exhausted?

• Do you frequently feel sick?

• Are you hot when others are cold, or cold when everyone else is warm?

• Do you have trouble thinking clearly, aka “brain fog”?

• Do you often feel irritable?

• Are you experiencing hair loss, dry skin, or unexplained weight fluctuation?

• Do your joints ache or swell but you don’t know why?

• Do you have an overall sense of not feeling your best, but it has been going on so long it’s actually normal to you?

IF you answered yes to any...

How the Immune System Works (The How it Works Series)

How the Immune System Works (The How it Works Series)
by Lauren M. Sompayrac (Author)


How the Immune System Works has helped thousands of students understand what’s in their big, thick, immunology textbooks. In his book, Dr. Sompayrac cuts through the jargon and details to reveal, in simple language, the essence of this complex subject. In fifteen easy-to-read chapters, featuring the humorous style and engaging analogies developed by Dr. Sompayrac, How the Immune System Works explains how the immune system players work together to protect us from disease – and, most importantly, why they do it this way. Rigorously updated for this fifth edition, How the Immune System Works includes the latest information on subjects such as vaccines, the immunology of AIDS, and cancer. A highlight of this edition is a new chapter on the intestinal immune system – currently one of the...

Super Immunity: The Essential Nutrition Guide for Boosting Your Body's Defenses to Live Longer, Stronger, and Disease Free

Super Immunity: The Essential Nutrition Guide for Boosting Your Body's Defenses to Live Longer, Stronger, and Disease Free
by Joel Fuhrman (Author)


In Super Immunity, world-renowned health expert and New York Times bestselling author of Eat to Live Dr. Joel Fuhrman offers a nutritional guide to help you live longer, stronger, and disease free.Dr. Fuhrman doesn’t believe the secret to staying healthy lies in medical care—rather, the solution is to change the way we eat. With more than 85 plant-based recipes, a two-week menu plan, and lists of super foods that boost immunity, Dr. Fuhrman’s proven strategies combine the latest data from clinical tests, nutritional research, and results from thousands of patients .Fans of Alejandro Junger’s Clean, Mark Hyman’s Ultraprevention, and T. Colin Campbell’s The China Study will appreciate Dr. Fuhrman’s practical plan to prevent and reverse disease—no shots, drugs or sick days...

Immune System: 101 Natural Ways to Boost your Immune System, Fight Germs, and Live a Healthy Life

Immune System: 101 Natural Ways to Boost your Immune System, Fight Germs, and Live a Healthy Life
by Living in Health (Author)


BOOST YOUR IMMUNE SYSTEM! 101 NATURAL WAYS TO BOOST YOUR IMMUNE SYSTEM, FIGHT GERMS, AND LIVE A HEALTHY LIFE Your immune system is the body’s only line of defense against both foreign and internal threats. It is clear therefore that you must maintain your immune system in the best possible condition for optimal health. It is not a myth that some foods are better than others at boosting our immunity. If you were ever wondering what might be the best foods in the world to help keep your immune system in the best shape, then this book is simply the way to go. It really helps to have a great defense mechanism to protect ourselves and it is only logical to have one. If you are still not convinced, then look at the amount of money any country spends on its defense, and compare it to...

Immune System Boosters: How To Naturally Boost Your Immune System & Stay Healthy All Year Long

Immune System Boosters: How To Naturally Boost Your Immune System & Stay Healthy All Year Long
by Boondocks Botanicals


Discover over 50 ways to naturally boost your immune system with medicinal herbs, natural antibiotics, lifestyle tips, and gut healthy foods.
Have you been wanting to learn ways to naturally increase your immunity system? Look no further. This book will give you the mother lode of information about using herbs, food and healthy living tips to bolster your immune system and increase your vitality.You’ll learn dozens of natural remedies, holistic techniques and recipes to strengthen your immune system including:
The Best Medicinal Herbs for Your Immune System
The Top Immune Strengthening Foods
How To Make an All Natural Anti-Bacterial Spray
Which Mushrooms Improve Immunity
Recipes for Probiotic Health
How To Use Essential Oils to Enhance...

The Immune System, 4th Edition

The Immune System, 4th Edition
by Peter Parham (Author)


The Immune System, Fourth Edition emphasizes the human immune system and presents immunological concepts in a coherent, concise, and contemporary account of how the immune system works. Written for undergraduate, medical, veterinary, dental, and pharmacy students, it makes generous use of medical examples to illustrate points. This classroom-proven textbook offers clear writing, full-color illustrations, and section and chapter summaries that make the book accessible and easily understandable to students. The Fourth Edition is a major revision that brings the content up-to-date and improves clarity. Based on user feedback, there is now increased continuity and connectivity between chapters.

The Immune System, 3rd Edition

The Immune System, 3rd Edition
by Peter Parham (Author)


The Immune System, Third Edition emphasizes the human immune system and synthesizes immunological concepts into a comprehensible, up-to-date, and reader-friendly account of how the immune system works.  Written for undergraduate, medical, veterinary, dental, and pharmacy students in immunology courses, it makes generous use of medical examples to illustrate points.  The Third Edition has been extensively revised and updated and includes two new chapters on innate and adaptive immunity, which explore the physical, cellular, and molecular principles underlying these responses to infection.  It also features enhanced coverage of aspects of innate immunity such as the complement system, Toll-like receptors, defensins, and C-reactive protein; the role of dendritic cells in initiating...

Boost Your Immune System: 7 Steps You Can Start TODAY To Regain Your Health and Prevent Disease

Boost Your Immune System: 7 Steps You Can Start TODAY To Regain Your Health and Prevent Disease
by InterConnections, LLC


Your immune system is the golden key to optimize your health and vitality! Your body has an innate desire to be well and to function optimally. If you don’t believe me, think about when you accidently scratch yourself or get a cut – your body naturally and automatically starts the healing process. Your body works 24/7 to always optimize your health. By incorporating these 7 steps into our daily life you can boost and help your body to become strong.

By following the steps in this book your body can begin to heal itself – this includes type 2 diabetes, heart disease, high cholesterol, specific types of cancer and liver disease – to name a few.

I used these exact techniques to create a healthy, strong body. I am now pain free, off all my medications and...

How the Immune System Works, Includes Desktop Edition

How the Immune System Works, Includes Desktop Edition
by Lauren M. Sompayrac (Author)


How the Immune System Works is not a comprehensive textbook. It's the book thousands of students have used to help them understand what's in their big, thick, immunology texts. In this book, Dr. Sompayrac cuts through the jargon and details to reveal, in simple language, the essence of this complex subject. Fifteen easy to follow lectures, featuring the uniquely popular humorous style and engaging analogies developed by Dr Sompayrac, provide an introduction to the 'bigger picture', followed by practical discussion on how each of the components interacts with one another. Now featuring full-color diagrams, this book has been rigorously updated for its fourth edition to reflect today's immunology teaching and includes updated discussion of B and T cell memory, T cell activation, vaccines,...

Health: Naturally Improve Your Immune System with Herbal Remedies, Essential Oils and More

Health: Naturally Improve Your Immune System with Herbal Remedies, Essential Oils and More
by Millenia Publishing


Your immune system is a natural defense of your body, and it’s an entire network of cells, organs and tissues that try to fight against invaders. This includes fungus, bacteria, viruses, and parasites. They’re just about everywhere. It can be in your home, backyard, or even in your office. If you have a healthy immune system, then it’ll stop these invaders from entering the body and wreaking havoc, but they’ll slip through if your immune system is down.

© 2016 BrightSurf.com