Exam 2

List at least three reasons why vertebrate models are preferable to invertebrate ones.

§  Shorter evolutionary distance from humans than invertebrates.

§  Stronger conservation of genes, metabolic pathways, and development

§  Similar cell types, organs, integrated physiological systems

§  Appropriateness for testing toxicity

§  Susceptibility to similar pathogens and diseases.

□    What is an added challenge working with vertebrates not found in other models?

§  Generation time, lifecycles longer… harder to really track.

More costly. Need to factor in care.

How has genomic evolution affected vertebrate phylogeny? Which landmark events in the stem-vertebrate lineage contributed to cladogenesis and species radiations, and approximately when did they occir?

o   Whole genome duplication. Vertebrates underwent it 2^n times. everytime it split, genes were gained and loss.

o   600 million years ago, first vertebrates.

o   500 million years ago, two whole genome duplications.

o   450 million years ago, split into bony fishes and not bony.

o   300 million years ago, the teleost specific WGD (8 duplications/paralogs).

What are Osteichthyes and what two clades branch from this node?

o   Osteichthyes are bony fish, and from those we get sarcoptyerygii and actinopytergyii.

Which branch gave rise to us?

o   The branch that gave rose to us was tetrapoda.

What are teleosts, and how do their genomes differ from those of other vertebrates? Which teleost groups have undergone additional genomic change, and what genomic evolutionary process occurred in the 60 million years following this event that accounts for genes “missing” today? (

Teleosts are a diverse group of bony fish characterized by their unique skeletal structure and specialized adaptations. Their genomes differ from those of other vertebrates primarily due to a whole genome duplication event, and specific groups like the cyprinids have undergone further genomic changes, leading to gene loss through processes such as gene duplication and subsequent degeneration.