gene linkage and sordoria Flashcards
What is the most diverse fungal phylum?
Phylum Ascomycota
What is the ascus?
The defining feature in a microscopic sexually structure
Where is the ascospores formed?
In the ascus and form in a linear order
What did Lindsay Olive discover?
Found that ascospore color is determined by the genotype of the spore.
What way do they reproduce?
both sexually and asexually
Each haploids spore’s phenotype is determined by what?
The spore colored allele it posesses
What is Plasmogamy?
The fusion of two hyphae together
What is Dikaryotic stage?
Cells have two haploid nuclei
What is Karyogamy?
Nuclei fuse together and create one diploid nucleus
What is meiosis in ascomycetes?
Results in four cells haploid ascospores
What is mitosis in ascomycetes?
Cells divide to form eight ascospores in an ascus
What is dispersal?
Mature ascus release the ascospores to start a new mycelium
What is sodaria fimicola?
Microscopic ascomycete that has a life cycle of 1-2 weeks. Spends most of its life in a haploid vegetative state.
What is tetrad analysis?
Tetrad refers to the four spores created after meiosis in the Ascomycota life cycle. allows us to follow the chromatid throughout the meiotic process.
What is gene linkage?
The tendency of genes that are located close to each other on the same chromosome to be inherited together during meiosis
What does tetrad analysis help us find?
- Helps us identify 2 of the 4 chromatids that participate in crossing over.
- The mapping of gene markers close to the centromere of the chromosomes
When traits are frequently seen inherited together we can create a what?
genetic map
What is genetic mapping?
When 2 traits are regularly inherited together, therefore we can determine that the genes are close together on a chromosome
What are the ways to make a linkage map?
Crossbreeding, tracking traits, or recombination frequency
What is the recombination frequency?
recombinants/total offsprings x 100%
Sordaria is good to use in labs for what experiments?
For conducting tetrad analysis for the segregation for spore colored mutants
How is ascospore color determined?
By the genotype of the spore. (It can be observed in the ascus)
Even during sexual reproduction does the fungi have to undergo meiosis before mitosis?
yes
Sordoria (ascomycetes) is all what cells?
haploid cells
What is produced in mitosis for the sordoria?
4 spores of each type (8 total) this shows gene linkage
When the ratio is 4:4 that means what?
no crossing over occurred
When the ratio is 2:2:2:2 that means what?
Crossing over has occurred and recombinant chromosomes has been produced
How can we count the asci?
By putting them under a glass slide and popping them. We can then count them under a microscope
Who discovered crossing over?
Thomas Morgan Hunt
How to find the percent of crossing over?
(total cross over/total number) = # then #/2
the percent will also be the gene distance number
What is the accepted value of crossing over?
26%
What are some examples of fungal phylum?
bakers yeast, truffles, and morrels
