DNA¶

DNA (Deoxyribonucleic acid) is a long, complex molecule found in nearly all living organisms that contains genetic instructions used in the development and function of living organisms. It is composed of four basic building blocks called nucleotides (adenine, thymine, guanine, and cytosine) arranged in a specific sequence, which determines the genetic information that an organism inherits and passes down to its offspring. DNA is located in the nucleus of cells in the form of chromosomes and can be replicated and passed on to new cells during cell division.```

It is estimated that about 8% of human DNA actually originated from viruses that infected our ancestors millions of years ago.

ancestors and inbreds¶

a person living today likely had around 2^40 ancestors, or approximately 1 trillion, ancestors 1,000 years ago. This estimate assumes that there is no interbreeding between ancestors, which is not always the case.

some genetic studies have suggested that all humans are at least 50th cousins, and possibly as closely related as 20th cousins. The degree of cousinship between two individuals depends on how recently they share a common ancestor. As humans have interbred and migrated throughout history, it is likely that we all share common ancestors at some point in the past.

possible humans¶

The total possible combinations of human DNA can be calculated using the formula 4^n, where n is the number of base pairs in the DNA sequence. The human genome contains approximately 3 billion base pairs, so the total possible combinations of human DNA can be estimated as:

4^3,000,000,000 = approximately 1.07 x 10^1,800,000,000

This number is so large that it is difficult to comprehend. It is estimated that there are only about 10^80 atoms in the observable universe, which is many orders of magnitude smaller than the number of possible combinations of human DNA. This highlights the incredible diversity and complexity of the genetic code, and the immense potential for variation within the human species.

total expressions¶

it is thought that the total number of humans who have ever lived is somewhere between 100 billion and 120 billion

it's estimated that the human genome has undergone many changes over the course of evolution, with an estimated 99.9% similarity between all humans. This suggests that a large portion of possible DNA expressions have occurred since the beginning of mankind.

It is estimated that approximately 108 billion humans have lived on Earth since the emergence of Homo sapiens about 300,000 years ago. The total number of possible unique DNA combinations in humans is estimated to be around 10^37.

Assuming each human individual had a unique DNA combination, the percentage of possible human DNA combinations that have occurred since the beginning of mankind would be 1 / 10^37 * 10^11, which is an extremely small number, essentially approaching zero. However, it's important to note that there is significant overlap in DNA between individuals, so the actual number of unique DNA combinations is much smaller than the theoretical maximum.

human dna matches¶

virus¶

It is estimated that about 8% of human DNA actually originated from viruses that infected our ancestors millions of years ago. These viral fragments have been passed down from generation to generation and are now an integral part of the human genome. Some of these viral DNA sequences have even been co-opted by the human body for beneficial purposes, such as helping to regulate gene expression or protecting against viral infections.

This amounts to around 100,000 pieces of viral DNA in the human genome.

oldest dna¶

The oldest record of DNA that has been successfully sequenced and identified is from a horse fossil that is approximately 700,000 years old. The fossil, which was found in the Canadian permafrost, contained a well-preserved bone fragment that was used to extract and sequence DNA.

In addition to the horse fossil, other ancient DNA samples have been successfully extracted and sequenced, including from fossils of Neanderthals and other extinct human relatives, as well as from animals such as woolly mammoths and ancient bacteria. These samples provide valuable insights into the genetic makeup and evolutionary history of these species.

It is worth noting that the ability to extract and sequence DNA from ancient samples is highly dependent on the conditions in which the samples were preserved, and not all fossils or other ancient materials will contain viable DNA. As a result, the oldest record of DNA that can be successfully sequenced is likely to continue to evolve as new technologies and techniques for DNA extraction and sequencing are developed.

clones¶

Cloning is the process of creating an organism that is genetically identical to another organism through a process called somatic cell nuclear transfer (SCNT). While many different animals have been cloned over the years, the most complex animal that has been successfully cloned is the sheep, specifically the famous sheep named Dolly.

Dolly the sheep was the first mammal to be cloned using the SCNT technique. She was born on July 5, 1996, and was created by scientists at the Roslin Institute in Edinburgh, Scotland, using cells from the udder of an adult sheep. Dolly was an exact genetic copy of the sheep from which the cells were taken.

The successful cloning of Dolly was a major scientific breakthrough and opened up new possibilities for genetic research and animal cloning. However, it also raised ethical concerns about the use of cloning technology and the potential consequences for both animal welfare and human health.

Since Dolly, many other animals have been successfully cloned, including cats, dogs, cows, pigs, and even some endangered species.

genome¶

The Human Genome Project, which was completed in 2003, identified the complete sequence of human DNA, which is estimated to contain approximately 3 billion base pairs. Since then, continued research has led to a better understanding of the structure and function of the human genome. While the majority of the human genome has been identified, there is still much that is not fully understood.

It is estimated that only about 1-2% of the human genome encodes for proteins, the functional molecules that perform a wide range of tasks in the cell. The rest of the genome is made up of non-coding DNA, which was once thought to be "junk" but is now known to play important roles in regulation of gene expression and other cellular processes.

There is a wealth of evidence for evolution, from observations of the natural world to the fossil record to the molecular evidence of DNA. Here are some of the key lines of evidence:

Fossil record: The fossil record provides evidence of the evolution of species over time. Fossils of extinct species that were clearly distinct from any species alive today demonstrate that evolution has occurred.

Comparative anatomy: The similarities in anatomy and structure among different species can be explained by a common ancestry. For example, the bones of the forelimbs of mammals such as humans, bats, whales, and birds all have the same basic structure, despite their differences in function, indicating that they evolved from a common ancestor.

Biochemistry: The similarities in biochemistry and genetics among different species also provide evidence of evolution. For example, all living things use DNA as the genetic material, and the DNA sequences of different species are often similar in specific regions, reflecting a common ancestry.

Geographic distribution of species: The geographic distribution of species can also provide evidence for evolution. For example, many species that are found on the same continents or island groups are more similar to each other than to species found elsewhere, suggesting that they evolved from a common ancestor and have diversified over time.

Natural selection: Observing the process of natural selection in action, such as the development of antibiotic resistance in bacteria, provides further evidence of evolution. Natural selection is the mechanism by which evolution occurs, and by observing it, we can see how populations of organisms change over time.

These are just a few examples of the many lines of evidence that support the theory of evolution.