文档介绍：Comparative Genomics and the Evolution of Animal Diversity
animals have essentially the same genes.
ways gene expression is charged during evolution.
manipulations that alter animal morphology.
evolution and human origins.
Outline
Our world is full
Of diversity.
Annelids: simple
repeating body
Segments.
Mollusks: twisted
or coiled.
But there is one
striking feature:
Most animals have
essentially the
same genes!!!
Topic 1:
Most Animals Have
Essentially the Same
Genes
Comparison of pufferfish, mouse and human
In spite of millions of years of
evolutionary divergence, pufferfish,
mouse and humans each contain about
30,000 genes. Every human gene has a
clear counterpart in the mouse genome;
and three quarters of human and
bufferfish genes can be unambiguously aligned.
Comparison of sea squirt and vertebrates
Sea squirt, a chordate,
contains half the number
of genes present in vertebrates.
sea squirt genome contains
6 different FGF (fibroblast growth factor ), while mouse and human genomes at least 22 FGF—each gene in the sea squirt duplicated into average of four copies in vertebrates.
From the parison, we can conclude:
The ic conservation is universal.
Increase in gene number is primarily due to the duplication
of genes already present rather than the invention of entire new genes.
How does gene duplication give rise to biological diversity?
There are two ways in which gene duplication can result in morphological diversity:
view: the duplicated new genes undergo mutation, this mutation creates genes encoding related proteins with slightly different activities.
view: the duplicated genes doesn’t necessarily take on new functions, but instead acquire new regulatory DNA sequence, which allows different copies of the gene to be expressed in different patterns within the anism. (a general mechanism we focus attention on)
Topic 2:
Three Ways Gene Expression Is Charged During