The Hologenome Concept and the Enduring Influence of Mothers beyond Neo-Darwinism

-


Review of of Rosenblatt et al. (2014)'s exploration of the hologenome concept and its emphasis on maternal influence in evolution:

The Hologenome Concept and the Enduring Influence of Mothers

Rosenblatt et al. (2014) propose a revolutionary perspective on inheritance and evolution through the hologenome theory. This theory expands the unit of selection in evolution from the individual organism to the holobiont, encompassing a host and its associated microbial communities.

The article emphasizes the crucial role mothers play in shaping the holobiont and its evolutionary trajectory. Maternal microbiota significantly influences offspring development, health, and fitness by vertically transmitting beneficial microbes across generations. This vertical transmission shapes the offspring's microbiome composition and function, impacting its adaptation and evolutionary potential.

The hologenome concept challenges the traditional Mendelian view of inheritance solely through nuclear DNA. It acknowledges the microbiome as a heritable and transmissible component that can influence host traits. This necessitates a reevaluation of evolutionary mechanisms, recognizing the significance of maternal effects and microbial inheritance in shaping the course of evolution.

Rosenblatt et al.'s work has sparked significant debate and opened new avenues for research in evolutionary biology. It underscores the importance of studying not just individual genomes but the hologenome, encompassing the host and its microbial partners. This broader perspective holds the potential to transform our understanding of how organisms evolve and adapt.

Delving Deeper into the Hologenome

The hologenome concept offers a new lens for examining host-microbe interactions and their influence on various aspects of biology. Here's a deeper dive into some key points:

  • Microbial Diversity and Function: The human microbiome itself is a vast and diverse ecosystem, harboring trillions of microbes from various species. These microbes play essential roles in digestion, immune function, metabolism, and even behavior.

  • Vertical Transmission Mechanisms: Mothers primarily transmit microbes to their offspring during birth, breastfeeding, and close contact. This transmission shapes the initial composition of the offspring's microbiome, influencing its development and health.

  • Evolutionary Implications: The hologenome concept suggests that selection pressures act not only on the host genome but also on the collective genome of the holobiont. This means that adaptations can arise through changes in the host genome, the microbiome, or interactions between the two.

The Future of Hologenome Research

Rosenblatt et al.'s work lays the groundwork for a new era of research in evolutionary biology. By studying the hologenome, scientists can gain a deeper understanding of:

  • The intricate interplay between hosts and their microbiomes

  • How microbial communities influence host health and disease susceptibility

  • The evolutionary forces shaping the composition and function of microbiomes

The journal article challenges the traditional concept of vertical inheritance, which posits that genetic information is primarily passed down from parent to offspring through DNA. The hologenome concept proposes a broader view of inheritance, arguing that the host and its microbiome (the collective community of microbes) together constitute a unit of selection, termed the holobiont. The holobiont's hologenome encompasses the host's genome and the microbiomes' genetic information.

This concept challenges vertical inheritance by highlighting the role of the microbiome in shaping phenotypes (observable traits) and fitness (an organism's ability to survive and reproduce). The microbiome can be influenced by various factors, including maternal inheritance during birth and early life. This suggests that mothers can significantly impact their offspring's hologenome and fitness not only through their own genes but also by shaping the offspring's microbiome.

The hologenome concept necessitates a reevaluation of inheritance patterns, moving beyond the sole focus on parental DNA to encompass the complexities of host-microbiome interactions.

The journal article suggests that mothers transmit their microbiomes to their offspring, potentially influencing the offspring's hologenome and its evolutionary trajectory. This maternal influence can extend beyond just genetics, impacting the offspring's epigenetic makeup. Epigenetics refers to the study of how genes are expressed without altering the underlying DNA sequence. The maternal microbiome can influence the offspring's epigenetic landscape by interacting with genes and altering their expression. This epigenetic inheritance can have lasting effects on the offspring's development, physiology, and even susceptibility to disease.

The journal article  challenges neo-Darwinism by proposing the holobiont, a consortium of a host and its microbiome, as a unit of selection in evolution. This broadens the evolutionary scope beyond the individual organism.

Neo-Darwinism emphasizes the role of genetic variation and natural selection in shaping individual traits. The hologenome concept argues that the microbiome significantly influences the host's fitness and can even be inherited through generations. This challenges the idea of the sole focus on the host's genome for evolutionary adaptation.

The article proposes that mothers, who shape the initial microbiome of their offspring, play a crucial role in holobiont evolution. This challenges the neo-Darwinian view of inheritance, which primarily focuses on DNA passed from parents to offspring.

In essence, the hologenome concept suggests a more intricate interplay between host genetics, microbial communities, and environmental factors in shaping evolutionary trajectories. Further exploration of the hologenome concept has the potential to revolutionize various fields, including medicine, biotechnology, and our understanding of life itself.



Comments

Post a Comment

Popular posts from this blog

No, the EES is not just a add on to Neo-Darwinism aka the Modern Synthesis

-
Image
" The summary of the state of affairs on the 150th anniversary of the Origin is somewhat shocking: in the post-genomic era, all major tenets of the Modern Synthesis fthe theory of evolution) are, if not outright overturned replaced by a new and incomparably more complex vision of the key aspects of evolution (EES). So, not to mince words , the Modern Synthesis is gone" -Eugene Koonin, an evolutionary biologist (Cited by over 270,000 evolutionary scientists.) The Extended Evolutionary Synthesis (EES) represents a significant departure from the traditional neo-Darwinian framework, also known as the Modern Synthesis . While both theories aim to explain evolutionary change, they differ fundamentally in their underlying mechanisms and the roles they assign to various biological processes. A crucial point of divergence lies in the interpretation and application of the term " evolutionary ," particularly concerning the incorporation of epigenetic mechanisms....
Read more

Is the random mutational model of evolution on its way out?

-
Image
While the random mutational model of evolution has long been a cornerstone of evolutionary biology, the Extended Evolutionary Synthesis (EES) and the study of epigenetics are challenging its core assumptions. The Random Mutational Model and Its Limitations The traditional view of evolution, often called the Modern Synthesis or neo-Darwinism , emphasizes random genetic mutations as the primary source of variation. Natural selection then acts upon this variation, favoring individuals with advantageous traits. This model has been successful in explaining some evolutionary phenomena, but it also has limitations: It struggles to explain complex adaptations: The idea that complex features like the eye or the immune system arose solely through random mutations seems statistically improbable. It overlooks the role of the environment: The traditional model treats the environment as a selective force, but it doesn't fully consider how organisms can actively respond to and s...
Read more

ERVs and Common Descent: A Reassessment in Light of Recent Findings

-
Image
Endogenous retroviruses (ERVs) have long been considered strong evidence for the common descent of humans and chimpanzees. These remnants of ancient viral infections, embedded in the genomes of both species, were once thought to be non-functional "junk DNA." The premise was that the shared presence of these seemingly random insertions in corresponding genomic locations could best be explained by a shared evolutionary history. However, recent research, such as the "Switching Sides" article published in May 2021, has challenged this assumption by demonstrating that ERVs play a functional role in the development of the human embryo and immune system. This discovery raises questions about the validity of using ERVs as primary evidence for common descent. The Traditional Argument for Common Descent The traditional argument for common descent based on ERVs rests on the following points: Random Insertion: Retroviral insertions are thought to occur randomly in...
Read more