Homology no longer means common ancestry


In the field of megagenomics, homology no longer means common ancestry. This is because homologous genes can be acquired through horizontal gene transfer (HGT), a process by which genes are transferred between organisms of different species. HGT is a common occurrence in bacteria, but it can also occur in other organisms, such as archaea and eukaryotes.

For example, a study published in the journal Nature in 2016 found that a gene that is essential for the metabolism of sulfur in the human gut was acquired from bacteria through HGT. This suggests that the human gut microbiota may play a role in the evolution of human metabolism.

The discovery that homology does not always mean common ancestry has implications for our understanding of the tree of life. It is now possible that some organisms that are closely related genetically may not be closely related evolutionarily. This is because they may have acquired their genes through HGT from other organisms.

The study of HGT is a rapidly growing field, and it is likely to have a major impact on our understanding of evolution. As we learn more about HGT, we will be able to better understand the relationships between different organisms and the evolution of life on Earth.

Here are some other examples of homologous genes that were acquired through HGT:

  • The gene for resistance to antibiotics in bacteria

  • The gene for photosynthesis in plants

  • The gene for lactose digestion in humans

These examples show that homologous genes can be acquired through HGT in a variety of organisms. This means that we cannot always assume that homologous genes are inherited from a common ancestor.

Here are 10 ways neo-Darwinism fails to explain homology:

  1. Homology is not always gradual. In some cases, homologous structures are very different from each other, and there is no clear evidence of a gradual transition between them. For example, the wings of bats and birds are very different in structure, but they are both homologous to the forelimbs of other mammals.

  2. Homology is not always due to common descent. In some cases, homologous structures can arise independently in different lineages. For example, the eyes of vertebrates and cephalopods are both homologous, but they did not evolve from a common ancestor.

  3. In some cases, homologous structures are not identical, and there are differences in their size, shape, or function. For example, the forelimbs of humans and dogs are homologous, but they are not identical.

  4. Homology is not always limited to physical structures. Homology can also apply to genes, proteins, and other biological molecules. For example, the genes for hemoglobin.

  5. The neo-Darwinian mechanism of random mutation and natural selection is not sufficient to explain the complexity of homologous structures. Many homologous structures are very complex, and it is difficult to see how they could have arisen through a series of random mutations.

  6. The neo-Darwinian mechanism of genetic drift is not sufficient to explain the distribution of homologous structures. Genetic drift is the random change in allele frequencies in a population. It can cause some alleles to become more common and others to become less common, but it cannot create new alleles.

  7. The neo-Darwinian mechanism of gene duplication is not sufficient to explain the complexity of homologous structures. Gene duplication is the process by which a gene is copied and then both copies become active. This can lead to the evolution of new genes, but it cannot explain the complexity of homologous structures that already exist.

  8. The neo-Darwinian mechanism of natural selection is not always directional. Natural selection can favor either the preservation of existing traits or the evolution of new traits. It is not always clear why natural selection would favor the evolution of homologous structures.

  9. The neo-Darwinian mechanism of natural selection is not always efficient. Natural selection can take a long time to produce significant changes in a population. It is not clear how natural selection could have produced the complexity of homologous structures in a reasonable amount of time.

  10. The neo-Darwinian mechanism of natural selection is not always reversible. Once a trait is lost, it is often difficult or impossible to regain it. This is not consistent with the observation that many homologous structures are reversible.

These are just some of the ways that neo-Darwinism fails to explain homology. There are many other problems with the neo-Darwinian theory of evolution, and it is clear that it is not a complete explanation for the diversity of life on Earth.

Comments

Post a Comment

Popular posts from this blog

Beyond the Sequence: The Epigenetic "Fingers" That Play the DNA Keyboard

Image
Imagine the keyboard itself is not a standard piano keyboard, but a modular synthesizer, capable of producing an almost infinite array of sounds. The DNA sequence, then, represents the fundamental building blocks of this synthesizer, the raw materials from which all sounds are generated. Epigenetics, our "fingers," manipulates these building blocks, adjusting parameters like volume, timbre, and rhythm, transforming the raw potential of the DNA sequence into a symphony of cellular functions. We can further refine the "fingers" analogy. Consider that each finger represents a distinct epigenetic mechanism: DNA methylation, histone modifications, and non-coding RNA.  DNA methylation, for instance, might be the "index finger," capable of precisely silencing specific genes, like muting individual keys on the synthesizer. Histone modifications, the "middle finger," could represent the ability to adjust the accessibility of the DN...
Read more

Why are Christian philosophers running towards Darwin while biologists are "running" away?

Image
As nature reveals the strength of epigenetics and the weakness of Neo-Darwinism, biologists are “running” away from the long-standing accepted theory. In The Federalist , April 2019, Benjamin Dierker reviews “Why one-third of biologists now question Darwinism”: "Current estimates are that approximately one-third of professional academic biologists who do not believe in intelligent design find Darwin’s Theory inadequate to describe all of the complexity in biology.” Dierker continues, “The important note is that these are not ideologues or religious zealots, nor do they propose a god or biblical solution.  Rather, they find problems in the lack of explanatory power of Darwin’s theory in light of modern understanding of mutation, variation, DNA sequencing and more. These expressions of doubt do not reject naturalism or evolution per se, but the rigor of the Neo-Darwinian model for explaining the development of life.” For 40 years, scientists calculated natural se...
Read more

Rewriting the Rules: Epigenomic Mutation Bias Challenges Randomness in Evolution

Image
This research challenges the long-held dogma that mutations occur randomly, irrespective of their consequences, by demonstrating a clear, epigenome-mediated mutation bias in Arabidopsis thaliana . The study meticulously unveils how mutation rates are not uniform across the genome but are significantly reduced in functionally constrained regions, particularly within gene bodies and essential genes. This discovery fundamentally alters our understanding of evolutionary processes, suggesting that mutation is not a purely directionless force. "Mutation bias reflects natural selection in Arabidopsis thaliana" This opening statement encapsulates the core finding: mutation rates are not random but reflect epigenetic pressures. The authors demonstrate that mutations are less frequent in crucial genomic regions, directly contradicting the prevailing theory of random mutation. This observation suggests an active mechanism that minimizes deleterious mutations in essentia...
Read more