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

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

”

The shared derived character that defines the Ascomycota is the

ascusascus. It is within the ascusascus 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. 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

S phase Meiosis I Meiosis II

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

Sordaria fimicola~ ASCOMYCOTA

How many DID NOT crossover?

No X-over

Sordaria fimicola~ ASCOMYCOTA

How many DID crossover?

Did X-over

Sordaria fimicola~ ASCOMYCOTA

How many DID crossover?

Total countedX 100

Sordaria fimicola~ ASCOMYCOTA

349

609X 100

Sordaria fimicola~ ASCOMYCOTA

. 573 X 100 = 57.3

Sordaria fimicola~ ASCOMYCOTA

How many DID crossover?

Total countedX 100

Divide this number by 2

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.