Genomes and their Evolution

1) What is genomics?

The study of the whole set of genes and their interactions.

2) What is a homebox?

Homebox is a 180-nucleotide sequence that specifies a 60-amino-acid homeodomain in the encoded proteins.

3) Explain the whole-genome shotgun approach to genome sequencing!

The whole genome is cut into many small, overlapping fragments that are sequenced; computer software then assembles the complete sequence. Correct assembly is made easier when mapping information is also available.

Facts:

- Websites on the Internet provide centralized access to genome sequence databases, analytical tools and genomerelated information

- Only 1.5% of the human genome codes for proteins or gives rise to rRNA or tRNA; the rest is noncoding DNA, including repetitive DNA

- Genomes vary in size, number of genes, and gene density

- Biologists in the field of evo-devo compare developmental processes of different multicellular organisms

- Duplication, rearrangement, and mutation of DNA contribute to genome evolution

Summary:

Sequencing the human genome is the most ambitious mapping project. It officially began as the Human Genome Project in 1990, in major, going through three stages: genetic mapping, physical mapping, and DNA sequencing. Humans have 20,488 genes and we can make 75,000 polypeptides. Humans and other mammals have the lowest gene density and the number of genes is not correlated to genome size.

It seems that the rate of duplications and inversions have accelerated about 100 million years ago.

Extra:

DNA Genechip