Lecture 32 Flashcards
What is a chytrid and what are Bd and Bs? Why were these able to rise in prominence?
A chytrid is a type of fungus, Bd infects frogs (and has made many species extinct, due to some frog species able to not get sick from it, keeping levels of the disease high, as well as no immunity development), Bs infects newts/salamanders. These diseases and many others have been able to become more dominant due to the rise in globalisation (pathogens able to become more dominant as they move out of their niche). In some frogs Bd will kill them while in others it will do no harm (leads to leaking of ions from thin skin). Bs leads to lesions on salamanders/newts.
Where are the chytrids believed to be from and what are the two major fungi groups? How do chytrids relate?
Chytrids are found outside of the two major ascomycota and basidiomycota fungi groups and is believed to possibly be from South America, though this is not known for sure.
How do chytrids grow?
Chytrids start out as a cell with a nucleus and a flagellum for movement, it will then develop small threads around its outside and then grow into a multi nucleate sporangium. Once this reaches maturity a pore will develop and lead to the process repeating, the spores will not move far from the sporangium and will lead to formation of more spores. In order to grow and spread well the chyroids need fresh water. They can be grown in the lab.
How was the chytrid genome compared and what did this show?
The chytrid genome is quite large and as such the genome was tested using PCR sampling. This PCR sampling showed that the chytrid is diploid (as in one position half had an A instead of the reference G, suggesting heterozygosity, these clones also had differences in other areas). If this is done in other locations around the world the same regions of the DNA show heterozygosity. This shows the organisms genetics is essentially a frozen clone (no meiosis), possibly an interspecific hybrid (like mules).
