DNA, Genetics and Epigenetics

Chromosomes

A chromosome is a thread-like structure made of DNA and protein that holds genetic instructions. It as a tightly packed package or an instruction manual inside your cells that tells your body how to grow and work. ¹

A double helix describes the structure of DNA. A DNA molecule is made up of two linked strands that wind around each other to resemble a twisted ladder in a helix-like shape.

Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.

Attached to each sugar is one of four nucleotides: adenine (A), cytosine (C), guanine (G) or thymine (T). These are the rungs of the ladder that connects the two strands. Adenine bonds with thymine and cytosine bonds with guanine.

A nucleotide consists of:

There are 4 nucleotides found in both DNA and RNA.

Humans usually have 46 total chromosomes arranged in 23 pairs inside almost every cell. You get one set of 23 chromosomes from your mother and the other set of 23 from your father. The final pair determines your sex. Females usually have two XX chromosomes and males usually have one X and one Y chromosome.

A Very Brief History of the Discovery of DNA

Key Milestones in DNA History ³

The DNA Codon

DNA codons are sequences of three nucleotide bases that code for specific amino acids, start signals, or stop signals during protein synthesis. There are 64 total combinations made from four DNA bases (Adenine, Thymine, Cytosine, and Guanine).

The nucleotide bases are read in groups of three. Each group matches one amino acid or a stop/start command that tells the cell where to begin reading and building a protein.

Most amino acids can be made by more than one different codon which is why there are only 26 slots in the codon wheel instead of the expected 64 (4 times 4 times 4).

DNA Methylation

DNA methylation is an epigenetic mechanism where a methyl group (CH₃) are added to DNA, altering gene activity without changing the underlying genetic sequence. Typically occurring at the cytosine nucleotide bases where it represses gene transcription by turning the gene off.

Lifestyle factors like diet, exercies, stress management, smoking and yoga can influence methylation. Nutrients including folate and vitamin B12 are also relevant.

The process is reversible where enzymes can remove methyl groups to reactivate genes.

Agouti Mice and Diet

Normal agouti mice have a grayish-brown appearance. Mice with a dominant mutant gene develop yellow fur, adult-onset obesity (they are much heavier), type 2 diabetes and a higher risk of tumors.

Our genome contains all the information to make us who we are but many of the details of our behavior and appearance are actually determined by gene regulation as well as conscious and sub-conscious choices. An example of the power of gene regulation is seen in agouti mice, in which genetically identical twins can look entirely different in both color and size. For example, one mouse may be small and brown, but her twin sister may be obese and yellow. Another genetically identical sister may have a mottled look with both fur colors present and fall in the middle of the weight range. The genome of each of these mice is the same but the gene expression differ.

In normal, healthy mice, the agouti genes are kept in the “off” position by the epigenome, which attaches methyl groups to the corresponding regions of DNA. In yellow, obese mice, the same genes are not methylated. These genes are expressed or “turned on.” The turning on of this single gene results in an apparent freak of nature. Mice whose agouti gene is “on” are also more likely to suffer from diabetes and cancer as adults.

One suspected trigger is a chemical found in many plastic drink bottles, including baby bottles, called bisphenol A. In one particularly notable study, scientist Randy Jirtle and his group of researchers exposed pregnant mice to bisphenol A. More of their genetically identical progeny developed into yellow, obese mice than would normally be expected. ⁵

Folic acid and vitamin B12, was shown to counteract the reduction in DNA methylation caused by bisphenol A. In addition, a constituent of soy products called genistein prevented an increased number of unhealthy offspring. ⁶

Extra folic acid, vitamin B12, choline and betaine also altered the coat colour in the child of the agouti parents ⁷

Important: Many studies that observe the impact of nutrition on mice use doses that far exceed the normal recommended ranges. These supplements conformed to recommended levels for humans who consumed a healthy diet rich in vegetables, leafy greens and fruit.

Bruce Lipton – His Views on Epigenetics

Bruce Lipton received a B.A. in biology from C.W. Post Campus of Long Island University in 1966 and a PhD in developmental biology from the University of Virginia in 1971. From 1973 to 1982, he taught anatomy at the University of Wisconsin School of Medicine, before joining St. George’s University School of Medicine as a professor of anatomy for three years.

He said that sometime in the 1980s, he rejected atheism and came to believe that the way cells function demonstrates the existence of God. Since 1993, he has taught primarily at alternative and chiropractic colleges and schools. Lipton has lectured at the New Zealand College of Chiropractic in Auckland. ⁸

Lipton has produced over 40 youtube pocasts. There are no transcripts so it is difficult to make notes. Also, it is not possible to rewind to review what was spoken.

According to Lipton, ⁹

Lipton was disparinging regarding his comment about the “secret of life”.

DNA meythlyalation only involves the cysteine neucleotide bases which account for 23% of the nucleotide bases in humans.

It is very easily disproved that “epigenetic mechanisms select either the maternal or the paternal gene”. People have been breeding dogs for specific characteristics for 10,000 years. ¹⁰

Consider the blood groups, A, B and O as well as Rh group. ¹¹ ~ ¹² ~ ¹³

If an A or B allele is paired in the two chromosomes inherited from your parents, the blood type is A, B or AB. A and B are dominant over O: Only if two O alleles are present is the O blood group found in the child.

The ABO blood group system was discovered in 1900 by the Austrian physician Karl Landsteiner, who identified the clumping reaction of red blood cells, named groups A, B, and O. He won a Nobel Prize in 1930. This explained why mixing wrong blood types could cause death and made blood transfusions safe.

The Rh blood group system was discovered in 1940 by Karl Landsteiner and Alexander S. Wiener.

The Rh blood group is one of the most complex blood groups known in humans. From its discovery 60 years ago where it was named after the Rhesus monkey, it has become second in importance only to the ABO.

The Rh blood type is an inherited protein on red blood cells which can be positive (Rh+) or negative (Rh-). You can safely receive both positive and negative blood. If you are Rh-, your red blood cells lack the Rh protein. Having this type is normal and healthy but you can only receive negative blood.

Western Europe descendants have a rate of Rh- blood of 15%–16%. African and East Asian, 1%–5% and native populations of America and Oceania are very low.

Rh incompatibility occurs when an Rh- mother carries an Rh+ baby. It does not harm the mother but causes severe health complications for the baby. If the baby is Rh+, the mother’s antibodies cross the placenta and destroy the baby’s red blood cells. Rh- are given Rh immunoglobulin shortly after birth.

My wife is Rh- and I am Rh+ so we and millions of others owe much to Karl Landsteiner and his colleagues.

There are many other examples where characteristics (including sex) are pass on as discrete units (genes) from both parents. This was first demonstrated by the Austrian Augustinian friar Gregor Mendel (1822-1884). Why are there hundreds of different varieties of tomatoes (and apples and corn)? ¹⁴

Last updated on Tuesday 11 August 2026 at 12:29 by administrators

1. National Human Geonome Research Institute (2026) National Human Geonome Research Institute – Nucleotide Available from: https://www.genome.gov/genetics-glossary/Nucleotide.
2. Price Bell, M. (2011) DNA Chemical Structure.
3. DNA Worldwide Group. n.d. “The History of DNA Timeline.” DNA Worldwide Group. https://www.dna-worldwide.com/resource/160/history-dna-timeline.
4. Watters, E. (2006) DNA Is Not Destiny: The New Science of Epigenetics. Science That Matters
5. Dolinoy, D. C. et al. (2007) Maternal nutrient supplementation counteracts bisphenol A-induced DNA hypomethylation in early development. Proceedings of the National Academy of Sciences. 104 (32), 13056–13061.
   
6. Adams, J. (2008) Obesity, epigenetics, and gene regulation. Nature.
7. Dolinoy, D. C. et al. (2006) Maternal genistein alters coat color and protects Avy mouse offspring from obesity by modifying the fetal epigenome. Environmental health perspectives. 114 (4), 567–572.
8. Wikipedia (n.d.) Bruce Lipton [online]. Available from: https://en.wikipedia.org/wiki/Bruce_Lipton.
9. Lipton, B. (Host). (n.d.). The Secret Key—DNA Methylation [Broadcast]. Bruce Lipton.
10. Zhang, Z. et al. (2020) Deciphering the puzzles of dog domestication. Zoological Research. 41 (2), 97–104.
11. Farhud, D. D. & Zarif Yeganeh, M. (2013) A brief history of human blood groups. Iranian Journal of Public Health. 42 (1), 1–6.
12. Dean, L. (2005) ‘Chapter 5 The ABO blood group’, in Blood Groups and Red Cell Antigens. National Center for Biotechnology Information. pp. 1–6. [online]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2261/.
13. Dean, L. (2005) ‘Chapter 7 The Rh blood group’, in Blood Groups and Red Cell Antigens. National Center for Biotechnology Information. p1-6. [online]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2261/.
14. Howard, J. C. (2009) Why didn’t Darwin discover Mendel’s laws? Journal of Biology. 2009 (1), 8–15.