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Continuing our examination of the biological mechanics of heredity.

Once again, this material is dense, so to fully appreciate everything that’s covered you may find it necessary to listen more than once. You might also like to consult the web page for this program to find the proper spelling for some technical terms, and for links to more in-depth explanations.

The last time we covered the macromolecular biosynthesis which goes on within every living cell – how proteins called polymerases transcribe DNA into RNA, and how proteins called ribosomes translate RNA into all the many proteins required for life to go on. We also touched briefly on the three main “domains” of life and the two main kinds of cells – the single-celled or unicellular prokaryotes, Archaea and Bacteria, and the unicellular and multicellular eukaryotes, or Eukaryota. It is this last class of life, the multicellular eukaryotic organisms, which includes all the forms of plant and animal life most familiar and most closely related to humankind, and which I therefore assign the most importance for the purpose of this primer.

This time we’ll review some key distinctions at the cellular level having to do with reproduction and genetic inheritance.

We’ve gotten a bit ahead of ourselves by talking about different types of cells before we even described what cells are. So we’ll start this time with the cell:

The cell (from Latin cella, meaning “small room”) is the basic structural, functional, and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently, and are often called the “building blocks of life”. The study of cells is called cell biology.

Cells are small, in most cases too small to see with the naked eye. It was the invention of the microscope which made the ubiquity of cells and the significance of their workings visible.

The cell was discovered by Robert Hooke in 1665. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.

In multicellular forms of life there are many different types of cells, each specialized to perform one specific function or another – blood cells, muscle cells, and nerve cells, for example. In animals, the most critical distinction in specialization is between germ and soma. This distinction was first made by the German evolutionary biologist August Weismann in the 1880s.

According to Weismann’s germ plasm theory, inheritance only takes place by means of the germ line, or germ cells, also known as gametes, such as egg cells and sperm cells. All the other cells of the body, called soma or somatic cells, do not function as agents of heredity.

Weismann pointed out that a germline cell:

is immortal in the sense that it is part of a lineage that has reproduced indefinitely since the beginning of life and, barring accident could continue doing so indefinitely.

Soma cells, in contrast, are mortal and serve merely as a vehicle for the germ line. Together they both serve as a vehicle for the genetic information of the organism, its biological inheritance, its genes, which we know now is encoded in its DNA.

As we saw with biosynthesis, as a general rule the flow of genetic information goes only one way, from DNA to RNA to protein. And likewise, as we see here, for multi-cellular reproduction there is a similar one-way relationship between germ and soma. Though all cells contain and make use of DNA to do what they do, it is only the germ cells – egg and sperm – which play the key role of carrying the genetic information, the blueprints of the organism, from one generation to the next during reproduction.

Those DNA blueprints, carried by the germ cells, contain the information how to build all of an organism’s cells, both germ and soma. The germ cells carry the essence of life, whereas the soma cells are the workers and materials, just as within each cell the various proteins and carbohydrates which are constructed and can perform construction only according to the information encoded and contained in the nucleic acids.

Within cells, at the molecular level, this general one-way rule was first identified by Francis Crick, one of the two men credited with discovering the double-helix structure of DNA. He called this one-way relationship the central dogma of molecular biology.

The analogous general one-way rule at the cell level was identified decades earlier, by Weismann. That one-way relationship, whereby genetic information only passes to the next generation via the germ cells, not the somatic cells, is called the Weismann barrier. The idea of the Weismann barrier is central to what biologists today call the modern evolutionary synthesis, though they don’t express it in the same terms.

These general one-way rules are important for two reasons. They help explain how evolution works, and how it doesn’t work.

Can a mutation in the DNA of one of your liver cells be passed on to your children? No. Your liver cells, like most of the cells in your body, are soma, and therefore the DNA in them is not passed on to your children. Only mutations in the DNA within germ cells have any chance of being passed on.

This is why Lamarckism is wrong, at least for multicellular organisms, including humans. Lamarckism is the idea that an organism can pass on to its offspring characteristics that it acquired during its lifetime, also known as heritability of acquired characteristics or soft inheritance. I direct you to Race and Genetics – Part 3 and the next few podcasts after it for a previous discussion of Larmarckism and how it fits into the hijacking of race science by “anti-racist” jews.

I use the qualifier “general” when describing these one-way rules because there are some exceptions. If you read what microbiologists have to say about the Weismann barrier today, for example, you see they have discovered evidence of horizontal gene transfer, the exchange of genetic information between organisms outside the usual, more thoroughly understood reproductive mechanisms. Different species, especially unicellular forms of life, and especially prokaryotes, appear to be swapping genes through the activities of retroviruses. Retroviruses are able to transfer genes between species because they reproduce by integrating their code into the genome of the host. If the cell they infect is a germline cell then that integrated DNA can become part of the gene pool of that species.

That’s close to the ultimate in virulence – a parasitic lifeform screwing with the DNA of the organisms which host it, mixing them together. Imagine the damage retroviruses could do if they were to organize to manipulate cell-level media and politics in order to actively suppress any anti-retrovirus immune response from their hosts.

There is another pair of biological terms whose meaning seems very similar to germ and soma, and which today are in even more common use. The terms are genotype and phenotype. In my layman’s understanding, I’ve always regarded the meaning of genotype as roughly corresponding with germ, and phenotype with soma – genotype meaning the stuff of inheritance, the payload, and phenotype meaning everything else, the vehicle for the genes.

Only recently did I try to find out why there are two pairs of terms, and what the technical distinction is. I was a little surprised by what I found, which comes from an article at The Embryo Project Encyclopedia titled Wilhelm Johannsen’s Genotype-Phenotype Distinction:

Wilhelm Johannsen first proposed the distinction between genotype and phenotype in the study of heredity while working in Denmark in 1909. The distinction is between the hereditary dispositions of organisms (their genotypes) and the ways in which those dispositions manifest themselves in the physical characteristics of those organisms (their phenotypes). This distinction was an outgrowth of Johannsen’s experiments concerning heritable variation in plants, and it influenced his pure line theory of heredity. While the meaning and significance of the genotype-phenotype distinction has been a topic of debate—among Johannsen’s contemporaries, later biological theorists, and historians of science—many consider the distinction to be one of the conceptual pillars of twentieth century genetics.

Genotype and phenotype are more general terms, referring to “dispositions” rather than cells, and applying as well to plants as animals. The meaning of Weismann’s terms germ and soma, in contrast, were based on what he saw and what was later determined to apply mostly to cellular reproduction in animals.

In describing the results of his experiments with plants, Johannsen referred to the group identity of the organism as its genotype and contrasted this with its phenotype, or the individual qualities of those organisms. The key phrases being group identity versus individual qualities.

Johannsen’s genotype-phenotype distinction has some similarity to August Weismann’s late nineteenth century distinction between the germ and soma, in that both thought that the causal interactions between an organism’s hereditary disposition and its physical characteristics was unidirectional. Although Johannsen acknowledged this affinity with Weismann’s ideas, he was unwilling to engage in what he considered to be unjustified speculations about the material basis of the genotype, as he argued Weismann had done.

It’s important to remember that Johannsen and Weismann did their research and made their fundamental distinctions before anything was known about the molecular-level mechanics, the DNA and biosynthesis within cells. I am perhaps still misunderstanding some subtlety here, but it seems that the more recent biological discoveries of DNA and the general one-way rule inside cells, Crick’s central dogma, have now firmly established the “material basis of the genotype”.

Setting aside the poisonous effects of politicization on science, which I get a whiff of in the wording of the Embryo Project Encyclopedia article on Johannsen, I think much confusion and defensiveness arises when scientists who are attempting to detect patterns and declare “rules” are confronted with a not-so-clean-cut reality. Reality tends to fit some coarse rules but also, due to the interaction of so many moving parts at different scales, turns out to be more complex than scientists at first imagine.

This does not make science or the broader rational pursuit of making sense of reality useless. When farmers who domesticated animals thought of and discussed heredity in terms of bloodlines, they weren’t entirely wrong, they just didn’t appreciate the finer details. Though they were ignorant of those details they were still able to manipulate the rules of reproduction and inheritance as they understood them.

Let’s make sure we understand what the terms genotype and phenotype mean by consulting some other sources. An article titled Evolution 101: Genotype versus Phenotype at berkeley.edu says:

An organism’s genotype is the set of genes that it carries. An organism’s phenotype is all of its observable characteristics—which are influenced both by its genotype and by the environment.

It goes on to provide the example of two cats, one with the usual ears and one with deformed ears, a difference rooted in their genes. As an example of a phenotype being altered by the environment it mentions flamingos, whose pinkness is not encoded in their genotype but results from the food they eat.

Wikipedia’s page on Genotype-phenotype distinction is more of the same, but adds an important aspect of phenotype that we haven’t mentioned yet:

“Genotype” is an organism’s full hereditary information. “Phenotype” is an organism’s actual observed properties, such as morphology, development, or behavior.

Behavior is not something most people think of as concrete in the same sense the physical shape or composition of a protein or cell or body is. “Anti-racists” have constantly and consistently tried to minimize and even deny the heritability of behavior, or personality traits. Though behavioral traits are less tangible, literally more difficult to see than material traits, the heritability of both is a fact that even semitically correct Wikipedia cannot yet erase.

Richard Dawkins coined the term extended phenotype to include all effects a gene has, inside and outside the body. Common examples include things like the dams and dam-building behavior of beavers, and the webs and web-spinning behavior of some spiders. It also includes the civilizations and civilization-building behavior of some races of humans.

Another type of extended phenotype Dawkins identified, which is also evident in humans, is the:

action at a distance of the parasite on its host. A common example is the manipulation of host behaviour by cuckoo chicks, which elicit intensive feeding by the parasitized host birds. These behavioural modifications are not physically associated with the host but influence the expression of its behavioural phenotype.

Dawkins summarizes these ideas in what he terms the Central Theorem of the Extended Phenotype:

An animal’s behaviour tends to maximize the survival of the genes “for” that behaviour, whether or not those genes happen to be in the body of the particular animal performing it.

I’ll bet in their thinking about life, neither Weismann or Johannsen ever dreamed of something so bizarre. Unless maybe they understood something about the jews.

We’ll wrap up this installment with one last pair of terms which are also in line with our germ and soma theme. The terms are haploid and diploid. Diploid cells have two complete sets of DNA, one set from each parent. All soma cells are diploid. Haploid cells, in contrast, have only one complete set of DNA. In animals the germ cells, the gametes (sperm and eggs), are haploid.

Image source: The Cellular Basis of the Immortality of Species.

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Race is rooted in biology. Physical and mental traits are heritable, mixed together and passed from parents to their children. The first hominids to domesticate animals must have had some grasp of this truth. Over time the understanding deepened and became animal husbandry, the science of breeding. What even pre-historic humans understood about animals they must have also seen applied just as well to themselves.

For a very long time racial inheritance could be thought of and described only metaphorically, using terms such as blood lines, with the importance of the semi-predictable recurrence of heritable traits encapsulated in terms such as pedigree.

Today we have a much more concrete idea of how heredity works, which is to say the biochemical mechanics of the process, or genetics. But in order to understand these workings we must learn a fair number of technical terms and concepts. Many racialists pick up this knowledge in bits and pieces. Unfortunately, in such circumstances we may need to hear or read a technical term many times before we come to appreciate what it means and how it relates to other terms. To make this process easier for beginners, and to help flesh out and reinforce the understanding some of you already have, I will attempt to lay out and connect here the most elementary terms and concepts of genetics.

Even though I will try make this as straightforward as I can, if much of this information is new to you, you will probably find it difficult to make sense of it all in one go. You may want to listen more than once. You may also find the text on the program page for this podcast more useful than usual, as it spells out all the technical words and provides many links you can follow to drill deeper than I intend to go.

Let’s start with biochemistry.

Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. By controlling information flow through biochemical signaling and the flow of chemical energy through metabolism, biochemical processes give rise to the complexity of life. Over the last 40 years, biochemistry has become so successful at explaining living processes that now almost all areas of the life sciences from botany to medicine are engaged in biochemical research. Today, the main focus of pure biochemistry is in understanding how biological molecules give rise to the processes that occur within living cells, which in turn relates greatly to the study and understanding of whole organisms.

Biochemistry is closely related to molecular biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life.

Yes, we’re interested mainly in the subset of biochemistry having to do with genetics, i.e. molecular biology:

Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interactions between the different types of DNA, RNA and protein biosynthesis as well as learning how these interactions are regulated.

We’ll get to proteins in a minute.

RNA and DNA are chemicals, or more specifically biochemicals, or organic chemicals. These are very different from the relatively simple inorganic chemicals you may recall studying in chemistry class. Even the smallest amount of a simple inorganic chemical, such as water, contains billions of identical and relatively small molecules moving about loosely. Each molecule of water is just two hydroden atoms joined with an oxygen atom – which is why it’s called H₂O. RNA and DNA molecules are far bigger and more complicated. They’re called macromolecules because they actually consist of millions of smaller molecules joined together in a long, thin chain.

DNA is an abbreviation for deoxyribonucleic acid. It is:

a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. DNA is a nucleic acid; alongside proteins and carbohydrates, nucleic acids compose the three major macromolecules essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix.

RNA stands for ribonucleic acid, a nucleic acid similar to DNA. RNA has:

biological roles in coding, decoding, regulation, and expression of genes. … Like DNA, RNA is assembled as a chain of nucleotides, but unlike DNA it is more often found in nature as a single-strand folded unto itself, rather than a paired double-strand.

That’s already alot of jargon to digest. Let me just reiterate the most important point: DNA and RNA are, together with proteins and carbohydrates, the very essence of everything that we call life. And you could say that DNA is the essence of the essence.

As an aside, the Swiss scientist Friedrich Miescher first discovered the nucleic acids in 1869. They’re called nucleic acids because they’re normally found only in the nucleus of a living cell. Miescher knew that, and suspected that the nucleic acids could have something to do with heredity, but he didn’t know how. In fact most of what we’re describing here was discovered long after 1869.

All we need to say here about carbohydrates is that they’re a class of biochemicals that perform numerous roles in living organisms. They serve mainly as fuel for metabolism, both as an energy source and as building blocks. The most abundant carbohydrate, cellulose, is a structural component of the cell wall of plants and in many forms of algae. Ribose is the carbohydrate that forms the backbone of RNA. Deoxyribose is a similar carbohydrate that forms the backbone of DNA.

DNA, RNA and proteins: The three essential macromolecules of life are all directly related. And it’s a circular relationship.

You can think of DNA and RNA as blueprints and proteins as workers. The chemical structure of DNA is more durable and redundant than RNA, thus DNA is the form the blueprints are kept in for long-term storage. When it’s time to build something, special proteins called polymerases attach to the DNA double helix and crawl along a portion of it – unzipping, copying, and rezipping – to produce a single short strand of RNA. This is called transcription.

A strand of RNA is essentially a partial, disposable copy of the DNA blueprints. Special proteins called ribosomes latch onto the RNA and use it as a template to manufacture protein molecules. This translation is called protein synthesis or biosynthesis.

(DNA Learning Center provides two excellent, narrated animations illustrating DNA transcription to RNA [source] and RNA translation to protein [source].)

What kinds of protein are produced? All of them. DNA includes the plans for every protein that life needs to live and reproduce, including the polymerases and ribosomes and other proteins that do all the work. Note the apparent chicken-and-egg problem. Polymerases and ribosomes are needed to build the polymerases and ribosomes. Biochemists understand alot about how biosynthesis works, and it’s actually more complicated than I’m describing. But it’s still a mystery to them how this complicated chemical mechanism ever get started.

To understand more precisely how DNA and RNA act as blueprints we need to describe their structure in more detail. As already mentioned, these macromolecules are long, thin chains of smaller molecules. The smaller molecules are called nucleobases or just bases. There are only four types. In DNA they are adenine, guanine, thymine and cytosine. In RNA uracil takes the place of thymine.

For our purposes it’s not important to remember the full names of these bases, much less their chemical structure. In fact, they are usually simply abbreviated as A, G, T (or U), and C. What is important is that you can think of these four bases as a four-letter alphabet in which information is encoded into DNA and RNA.

Recall that during translation a ribosome translates a bit of RNA into a protein. It actually does this by “reading” the sequence of bases one triplet at a time. AAC, GCG, UGA, … there are 64 unique combinations. Each different combination causes the ribosome to add a different kind of building block to the protein it’s assembling. These building blocks are called amino acids.

Recall that proteins, like RNA and DNA, are macromolecules. What happens is the ribosome combines these amino acids to form a greater number of even larger building blocks called peptide chains (AKA “polypeptides”). These chains are then assembled into the vast number of different proteins needed for life.

One interesting aspect of RNA translation is that it produces only about 20 different amino acids, because some of the 64 combinations of base triplets actually translate into the same amino acid. For example, UUU and UUC both translate into the amino acid abbreviated Phe. This redundancy provides some tolerance for mutations. If one base in the genetic sequence somehow changes into another there’s a chance that it will not have any noticable effect on the protein being manufactured.

Beyond DNA, RNA and proteins the next larger building blocks involved in the biomechanics of life are cells. There are two distinct types of cellular organization – the prokaryotic and eukaryotic – and a surprising relationship between them:

Living things have evolved into three large clusters of closely related organisms, called “domains”: Archaea, Bacteria, and Eukaryota. Archaea and Bacteria are small, relatively simple cells surrounded by a membrane and a cell wall, with a circular strand of DNA containing their genes. They are called prokaryotes.

Virtually all the life we see each day — including plants and animals — belongs to the third domain, Eukaryota. Eukaryotic cells are more complex than prokaryotes, and the DNA is linear and found within a nucleus. Eukaryotic cells boast their own personal “power plants”, called mitochondria. These tiny organelles in the cell not only produce chemical energy, but also hold the key to understanding the evolution of the eukaryotic cell.

The complex eukaryotic cell ushered in a whole new era for life on Earth, because these cells evolved into multicellular organisms. But how did the eukaryotic cell itself evolve? How did a humble bacterium make this evolutionary leap from a simple prokaryotic cell to a more complex eukaryotic cell? The answer seems to be symbiosis — in other words, teamwork.

Evidence supports the idea that eukaryotic cells are actually the descendents of separate prokaryotic cells that joined together in a symbiotic union. In fact, the mitochondrion itself seems to be the “great-great-great-great-great-great-great-great-great granddaughter” of a free-living bacterium that was engulfed by another cell, perhaps as a meal, and ended up staying as a sort of permanent houseguest. The host cell profited from the chemical energy the mitochondrion produced, and the mitochondrion benefited from the protected, nutrient-rich environment surrounding it.

DNA-based life seems to have developed in several steps, each with an increasingly complex structure. First came the single-celled prokaryotes, then some prokaryotes joined to form single-celled eukaryotes, and then eukaryotes somehow joined in multicellular arrangements to form all the larger organisms – the plants and animals.

Actually, there’s another chicken-and-egg problem here. Even the most primitive life, the prokaryotes, need DNA. Yet DNA cannot function outside of the protection of a cell. So how did this arrangement come into being in the first place? Once again biochemists don’t really know.

The key difference between prokaryote and eukaryote are the mitochondria, the little vestigal prokaryotic “power plants” embedded in each eukaryotic cell. While each eukaryote contains the DNA it needs to build everything else it needs – that DNA does not include the instructions for building the mitochondria. The mitochondria have their own DNA.