Human vs pig and chimpanzee DNA

This looks like a homework question to me so I will not help you unless you try and do a bit by yourself.

Here is a clue to help you with your research

The latin names for humans, chimps and pigs are Homo sapiens, Pan troglodytes and Sus scrofa respectively.

I'm 72 years old and I would like a scientific answer to the above question, please

Dear Jim,
A draft version of the pig (Sus scrofa) genome has recently been completed. See NCBI Pig Genome Resources
I haven't seen any overall % identity number, but one can say The pig genome is of similar size (3 x 10^9 bp), complexity and chromosomal organization as the human genome. This is from http://www.genome.gov/Pages/Research...eSEQ021203.pdf

The human chimp comparison is well known. If you compare the single nucleotide polymorphisms (SNPs), the genomes are a little less than 99% identical. This identity between two unrelated humans is about 99.9%. Neither of these comparisons include the loss & gains of DNA termed indels. These differences are also called copy number differences & there isn't an easy number of expressing this difference. An example of a copy number difference between humans is the gene responsible for color blindness. One way of making this comparison is to identify regions which are highly similar from the genetic maps. These regions are called syntenic segments. The expectation is that the size of the regions will decrease the further apart (time since the last common ancestor) the species are.

So how similar are our genes to a pig or a chimp? For this question I choose 1 gene. I compared albumen gene. The human (GenBank: NM_000477) to the chimp (GenBank: XM_517233) and to the pig (GenBank: NM_001005208) albumin mRNA sequences. I compared the sequences pairwise with program called BLAST (Basic Local Alignement Search tool) at the NCBI (BLAST: Basic Local Alignment Search Tool)

The Human vs Pig albumen genes are 83% identical (Identities = 1739/2091, Gaps = 80/2091 (3%)).
The Human vs Chimp albumen genes are 99% identical (Identities = 2119/2136, Gaps = 0/2136 (0%)).
The Chimp vs Pig albumen genes are 82% identical (Identities = 1668/2017, Gaps = 84/2017 (4%)).

You can make a nice argument for evolution with your question. If the pig, chimp & human albumin genes were the products of a separate creation there would be no reason to believe that the ~350 nucleotide differences between the human and the pig would the same as the ~350 differences between the chimp and the pig. I haven't done this multiple sequence alignment. It might never have been done. BUT, it is easily done & I would predict, based on the evolutionary relationships, that >90% of the differences with the pig will be shared between the human & chimp sequences.

Actually I can not add to these suspicions seeing as how I had the same question this morning as Jim above and was please, if not surprised to see the question posed and also answered this morning, with a suspicion over evolution which had motivated my search.
I will follow this thread however and add to it if I come up with anything more!

Hi Jem,
Can you recommend an authoritative and accessible primer for someone who wants to understand how these comparisons are made in more detail?

That is, me. I have a general background, but I have not read up on this for several years and would like to get a better handle on the different ways that cladistic trees are constructed from molecular data.

Hi Jem

Under your reasoning could it be argued that instead of man evolving from pig and chimp, can it be argued that pig and chimp may have evolved from man?

no, we didn't evolve from any animal alive today (chimps or pigs). We share a common ancestor with both. We have a much more recent common ancestor with chimps. The dates derived from DNA and from other scientific fields are in remarkable agreement.

Is it possible to find out if pigs dna contain human genes, as if a wild pig was taken and fused with human dna? In this case human dna wouldn't contain pig dna. I heard of a theory and would like to know how valid it is. According to this theory, humans were created in a similair way using primate and alien dna.

RedAngel,

Yes it is true but the aliens are actually us.

I am not a biologist so I can't give you the specifics.

It was mooted at one stage that a person requiring a lung transplant would have their DNA injected in to a pig fetus solely for the purpose of overcoming the problem of rejection. Even though pigs are a long way from us in terms of common ancestors the size of their organs appears to be an attractive feature.

I think the other avenue of exploration centred on the possibility of eliminating the gene in pigs that cause humans to reject pig organs. In other words, the greatest problem when it comes humans receiving pig organs is rejection.

Tut