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

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

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!

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

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

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

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

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

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

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA Meiosis II Meiosis I S phase

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

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

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

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

Sordaria fimicola~ ASCOMYCOTA 349 X 100 609

Sordaria fimicola~ ASCOMYCOTA . 573 X 100 = 57.3

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

Sordaria fimicola~ ASCOMYCOTA . 573 X 100 = 57. 3 / 2

Sordaria fimicola~ ASCOMYCOTA = 28 .65

Sordaria fimicola~ ASCOMYCOTA = 28 .65 this means 28.65 MAP UNITS

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.