molecular homology

molecular homologyArgument #3 for Common Descent

The sequence of amino acids in hemoglobin is very similar in chimpanzees and humans.

Neo-Darwinists say the best explanation for this similarity is that chimpanzees and humans are descendants of a common ancestor.

molecular homology: case for

As proteins evolve over time, their amino acid sequences have changed a little bit at a time.

The more time they have had to change, the more different they will appear from one another.

By comparing the differences between the sequences of the same protein in different species, evolutionary biologists can determine when the two species split off from their common ancestor and began to evolve independently.

molecular homology: case for

http://evolution.berkeley.edu/evolibrary/article/0_0_0/lines_08

http://www.pbs.org/wgbh/evolution/educators/lessons/lesson3/act2.html

http://www.pbs.org/wgbh/evolution/library/04/4/l_044_02.html

http://www.nap.edu/openbook.php?record_id=6024&page=17

http://evolution.berkeley.edu/evolibrary/article/evo_17

http://www.darwinismrefuted.com/myht_of_homology_04.html

online resources molecular homology: case for

Critics of Neo-Darwinism argue that it should not be surprising that hemoglobin in different organisms are similar in sequence and structure, because they are performing the same function.

Molecular similarities may reflect common functions.

molecular homology: a reply

If Darwin’s Tree of Life is correct, then we should expect that different types evidences would all point to the same tree.

Many scientists argue that this is often not the case.

A family tree based on anatomy may show one pattern of relationships, but a tree based on DNA may show quite another.


For example, if we look at mitochondrial cytochrome b gene produces a tree in which cats and whales are in the order of Primates.


But, if you analyze the anatomy of each, a different tree emerges. The cats belong to the order of Carnivora, and whales to Cetacea, neither being a Primate.


If all of these organisms really did evolve from a single common ancestor, only one of the trees can be right.

Critics point out that the real problem is that Universal Common Descent is wrong.

In other words, the reason that the trees don’t agree is that the organisms do not share a common ancestor.

Some evolutionary biologists agree. Carl Woese from the University of Illinois is one. He thinks that biology should abandon the idea of common descent. He says that life probably had multiple, independent starting points.


Biologist used to think that the genetic code was the same for everyone.

This means that genes code for the same protein in almost identical ways.

For example, the code for hemoglobin is the same code in humans, monkeys, lions, tigers and bears.


Is it the same?

No! Since 1985 scientists have discovered 18 different genetic codes. Many are very different from the standard code.

The standard code has 3 different mRNA stop codons: UGA, UAA, and UAG.

A codon is a group of 3 base pairs that match with a tRNA.

A stop codon, tells the cell to stop building the protein - it is now finished.


Of the 18 other codes discovered, they only have one stop codon, UGA.

The other 2 codons code for a certain amino acid.

If an organism was going to change from the standard code to the new one, it is hard to imagine how.

Changing to this new code would cause the cell to produce useless strings of extra amino acids when it should have stopped the protein production.

Having extra amino acids in a protein is a serious problem - the protein will not function properly.


This leaves the organism with 2 options:

1. simultaneously get a new set of genetic information that matches the new code (Nearly all biologist think that this is highly unlikely)

2. Die


resourcesEvolution Exposed by Roger Patterson

Speciation - page 57-67 Homology - page 68-72

Fossils (transitional) - page 73-74 Molecular Homology - page 74-75

Embryology - page 95-96

Refuting Evolution by Jonathan Sarfati

The Politically Incorrect Guide to Darwinism and Intelligent Design by Jonathan Wells


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