• DNA is a very, very long molecule -  it contains 3 billion base pairs

• A base pair is A=T, or C=G

• A base pair is two bases.

• The bases are Adenine, Thymine, Cytosine and Guanine

• The bases pair up in complimentary base pairing:

  • Cytosine = Guanine 

  • Adenine = Thymine

• The way I remember this is

  • C=G : The curvy ones like to spoon

  • A=T: The straight ones go together

• These bases pairs are the 'rungs' on the twisted ladder

• The sides of the ladder are sugar (either ribose or deoxyribose) and phosphate

• The sides go: Phosphate, sugar, phosphate, sugar, phosphate, sugar, phosphate...

• From one side to the rung to the side, we go: 

• Phosphate, Sugar, Base, Base, Sugar, Phosphate  

• A nucleotide is one complete side 

• A nucleotide is: Phosphate, Sugar, Base

• DNA = Deoxyribonucleic Acid

• Deoxyribose is the type of Sugar DNA has

• Nucleic Acid is the bases: Adenine, Thymine, Cytosine, Guanine 

• DNA is coiled up into a twisted ladder shape, called a Double Helix

• Helix because of its spiral pattern

• Double because of its two sides, or the side - rung, rung - side pattern of the ladder

• 1 length of DNA is called a Chromosome

• The largest human chromosome is chromosome 1

• It has: 249 million nucleotide base pairs

• More exactly it has: 248,956,422 base pairs 

• Humans have 23 pairs of chromosomes per cell

• They are labelled 1-22 based on size, chromosome 23 are the sex chromosomes

• Add up the bases in all 23 Chromosomes, you end up with 3000 Million Base pairs - or 3 Billion

• Chromosome 1 has  1,961 Genes 

• A Gene is a Length of DNA that codes for a Protein

• Proteins are important

• We have two copies or each gene 

• One from mum and one from dad

• If these copies are identical then we have Homologous Alleles

• But they can be different - due to ancestral mutations 

• If they are different, we can still get the exact same protein with the same amino acid sequence due to the fact that several different codons can code for the same amino acid (redundancy)

• If they are different, we could get a different amino acid. This might result in a change of shape and function of the protein

• This is the basis of variation 

• A slightly different protein. A protein with a slightly different shape may result in slightly different activity

• This slightly different activity of the slightly different protein might be an advantage depending on the environment

• The slightly different protein might be a growth factor giving you bigger muscles

• In the right environment this might be beneficial

  • E.g Myostatin mutation in Eddie Hall 

• In the wrong environment this might be harmful

  • E.g Myostatin mutation in Belgian Blue means they cannot be born normally and need to be delivered by a Vet

• Sometimes it has no effect at all

  •  E.g The variation we see between each other

• We have two copies for each gene

• If they are different then we have Heterozygous alleles

  • Hetero means different

• Heterozygous Alleles means that the two versions of the gene are slightly different

• This means that the 2 proteins created are slightly different

Belgian Blue Bull - A mutation in the Myostatin Gene -

Eddie Hall - one of the strongest people in the world, also has this mutation

"The Belgian Blue has a natural mutation in the myostatin gene which codes for the protein, myostatin ("myo" meaning muscle and "statin" meaning stop).[5] Myostatin is a protein that inhibits muscle development. This mutation also interferes with fat deposition, resulting in very lean meat.[5] The truncated myostatin gene is unable to function in its normal capacity, resulting in accelerated lean muscle growth. Muscle growth is due primarily to physiological changes in the animal's muscle cells (fibers) from hypertrophy to a hyperplasia mode of growth. This particular type of growth is seen early in the fetus of a pregnant dam, which results in a calf that is born with two times the number of muscle fibers at birth than a calf with no myostatin gene mutation.[5] In addition, a newborn double-muscled calf's birth weight is significantly greater than that of a normal calf". Directly Copied and Pasted from Wikipedia.