1. AP LAB #3
part C
Crossing Over during Meiosis in Sordaria… counting map units

2. Sordaria fimicola is a type of FUNGUS, found in the group known as ASCOMYCOTA
“Sac fungi”

3. Ascus are found in here… in the ascocarp!
The shared derived character that defines the Ascomycota is the ascus. It is within the ascus that nuclear fusion and meiosis take place.
Ascus are found in here… in the ascocarp!

4. Sordaria fimicola~ ASCOMYCOTA
See, here they are… ASCI!

5. Sordaria fimicola~ ASCOMYCOTA
This is what it looks under a scanning e- microscope!

6. Sordaria fimicola~ ASCOMYCOTA
Here they are… ASCI! ~ they hold ASCOSPORE

7. Sordaria fimicola~ ASCOMYCOTA
Here they are… ASCI! ~ there are chromosomes inside those dots!!

8. In the ascus, meiosis occurs, followed by a round of mitosis
In the ascus, meiosis occurs, followed by a round of mitosis. This leaves eight nuclei, and eventually eight ascospores
THERE ARE CHROMOSOMES INSIDE THOSE SPORES… AND WITHIN THE CHROMATIN, THERE ARE GENES….
These genes code for traits…
COLOR

10. Ascospores are formed within the ascus by an enveloping membrane system, which packages each nucleus with its adjacent cytoplasm and provides the site for ascospore wall formation

11. Sordaria fimicola~ ASCOMYCOTA

12. Sordaria fimicola~ ASCOMYCOTA
Meiosis II
Meiosis I
S phase

13. Sordaria fimicola~ ASCOMYCOTA

14. Sordaria fimicola~ ASCOMYCOTA

15. Sordaria fimicola~ ASCOMYCOTA

16. Sordaria fimicola~ ASCOMYCOTA

17. Sordaria fimicola~ ASCOMYCOTA
No X-over
How many DID NOT crossover?

18. Sordaria fimicola~ ASCOMYCOTA
Did X-over
How many DID crossover?

19. Sordaria fimicola~ ASCOMYCOTA
How many DID crossover?
X 100
Total counted

20. Sordaria fimicola~ ASCOMYCOTA
349
X 100
609

21. Sordaria fimicola~ ASCOMYCOTA
. 573
X 100 = 57.3

22. Sordaria fimicola~ ASCOMYCOTA
Divide this number by 2
How many DID crossover?
X 100
Total counted

23. Sordaria fimicola~ ASCOMYCOTA
. 573
X 100 = / 2

24. Sordaria fimicola~ ASCOMYCOTA=

25. Sordaria fimicola~ ASCOMYCOTA
= this means MAP UNITS

26. Sordaria is a haploid organism for the majority of its life cycle
It becomes diploid only when mycelia fuse and two different types of haploid nuclei form a diploid nucleus.