Biology



Biology

1. Compare the human, cow and birds (DNA) (NCBI), humans to birds cows to birds).

(% change should be human to cow )

Regulating a structural protein allows it to be used in many cell locations in many ways just by having a long complex region in the DNA that controls the genes expression for every eventuality in all cell types. This is why humans, cows and flies can share so many genes. They are regulated to be on and off differently to grow a different body.

The DNA of a cow and a whale, two mammals, should be more alike than the DNA of a cow and a bacterium. If it were not so, then the whole idea of DNA being the information carrier in living things would have to be questioned. Likewise, humans and apes have a lot of morphological similarities, so we would expect there would be similarities in their DNA. Of all the animals, chimps are most like humans, so we would expect that their DNA would be most like human DNA.[1]

Mammals can have only 20,000 -25,000 genes but by using regulated splicing variants produce maybe ~90,000 proteins by mixing and matching introns. Think of it as modular architecture.This collection of genes only takes up at most 2% of the lineal space in the chromosomes. This leaves plenty of room for all possible regulation sequences to control each gene for each cell type multiple ways. This still leaves room for histone binding sites, MARs (matrix attachment regions), & ncRNA transcription frames. What was once 'junk' DNA is rapidly becoming well defined regulatory elements that impact gene expression and handle DNA during cell replication.

(% change should be human to birds )

In a study of seven species of diving ducks, the control region divergence was less than 17 percent. This translates to 1700 - 2500 generations, which at a few years per generation is also in the several thousands of years range. Another study of closely related species of birds found that the difference in total mitochondrial DNA was about 5 percent or less. This probably translates to about 20 percent in the control region, and thus about 2000 to 3000 generations. With 2 or 3 years per generation, this again translates to a separation time of a few thousand years ago.[2]

It is now believed that the differences between us and chimps is how these sequences are turned on and off and to what degree in protein produced in each group. Compared to birds though, there should be many more DNA sequences that mutated since the split between humans and chimps, there were several species of bipelalism pre-humans after the split until homo sapiens emerged. In birds, their body shape has very few variations in structure across the entire species so I do not think they had more time since their common ancestor split.

(% change should be cow to birds )

Cows are mammals, and chickens are birds. The Mammalian and Avian animals as part of the Kingdom Animalia ...