Some animals have relatively large genomes with few genes. For instance flies have a genome twice the size of a nematodes, yet the nematode has over 6,000 more genes than a fly. Humans have a genome 10 times the size of both these animals but they have about the same number of genes as the nematode. The reason this can still provide the human with a large enough variety of proteins is that many of these genes are able to be spliced into different proteins through the use of alternate splicing of exons.
What are the three stages of genome sequencing?
1. Linkage map: markers are found all along the chromosomes recombination frequencies are used to determine the distances between them. These markers can be either genes, STRs or RFLPs.
2. Physical map: a physical distance between markers is determined. Then fragments of DNA are replicated so they can be overlapped to determine the order of them within the chromosome.
3. DNA sequencing: The ultimate goal is to know the nucleotide sequence of each chromosome. Now there are machines and computer programs that are able to help with this process
What is the effect of hox gene expression during development in crustaceans and insects?
Over time through the evolution of four different expressions of hox genes the different body shapes of these organisms has developed. This can be seen in the difference of body shape of the shrimp and grasshopper. The hox genes expression is responsible for morphological differences of species.
Facts:
- evo-devo is the study of evolutionary development biology
- Multigene families are collections of two or more identical or very similar genes
- In the human genome only 1.5% of it actually codes for rRNA and tRNA
- Genomics is the study of a whole set of genes within a species
- Bioinformatics is the application of computational methods to storage and analysis of biological data
This is a mapping of protein interactions. This is the statistically likely interaction between all the proteins found in an organism as predicted and mapped by a computer program.
Summary:
Scientists have begun to map genomes in order to determine things about animals their relationship to each other and the evolution of them. Databases and Internet tools help to pick out the sequences within a genome that actually code for a protein or the likely hood that one will. Some genomes are larger than others with smaller amounts of coding DNA this is a result of alternate splicing, transposable DNA, and repeating sequences. Alternation within structure of chromosomes, duplications, rearrangement of genes ect give the variety of genes that allows for evolution and study of these changes help the trace of evolution. The difference between expressions of genes such Hox genes change the developmental stages of organisms and change their body shapes.
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