Meiosis and Genetic Diversity in Sordaria

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Meiosis and Genetic Diversity in Sordaria
Biology 110 Lab

Results
Individual Data:

Non-recombinant| Recombinant| Total # of Asci| Total # Recombinant Asci(B + C)| Frequency of Recombinant Asci(B + C)/total # asci)| Frequency of Type B Asci(B/total # asci)| Frequency of Type C Asci(C/total # asci)| Ratio B/C| # of Type A Asci(4:4)| # of Type B Asci(2:4:2)| # of Type C Asci(2:2:2:2)| | | | | | | Tan Spore Color| | | |

14| 6| 6| 26| 12| (6+6)/26= 6/13| 6/26= 3/13| 6/26= 3/13| 6/6= 1| Gray Spore Color|
| | | | | | | | |
This table represents the number of asci observed individually. Out of the twenty-six asci observed, twelve of them were recombinant. The other fourteen observed were seen to have no crossing over.

Group Data:
Non-recombinant| Recombinant| Total # of Asci| Total # Recombinant Asci(B + C)| Frequency of Recombinant Asci(B + C)/total # asci)| Frequency of Type B Asci(B/total # asci)| Frequency of Type C Asci(C/total # asci)| Ratio B/C| # of Type A Asci(4:4)| # of Type B Asci(2:4:2)| # of Type C Asci(2:2:2:2)| | | | | | | Tan Spore Color| | | |

32| 19| 19| 70| 38| 38/70| 19/70| 19/70| 19/19=1|
Gray Spore Color|
| | | | | | | | |

This table represents the number of asci observed by two groups who shared their data. Out of seventy asci observed, thirty-eight were recombinant. The other thirty-two asci observed showed no crossing over. Section Data:

Section Data:

This table represents the number of asci observed by the entire class. Out of one hundred and fifty-two total asci observed, eighty-six were recombinant. The other sixty-six observed were seen to have no crossing over.

Non-recombinant| Recombinant| Total # of Asci| Total # Recombinant Asci(B + C)| Frequency of Recombinant Asci(B + C)/total # asci)| Frequency of Type B Asci(B/total # asci)| Frequency of Type C Asci(C/total # asci)| Ratio B/C| # of Type A Asci(4:4)| # of Type B Asci(2:4:2)| # of Type C Asci(2:2:2:2)| | | | | | | Tan Spore Color| | | |

66| 53| 33| 152| 86| 86/152| 53/152| 33/152| 53/33| Gray Spore Color|
| | | | | | | | |
Course Data:

Non-recombinant| Recombinant| Total # of Asci| Total # Recombinant Asci(B + C)| Frequency of Recombinant Asci(B + C)/total # asci)| Frequency of Type B Asci(B/total # asci)| Frequency of Type C Asci(C/total # asci)| Ratio B/C| # of Type A Asci(4:4)| # of Type B Asci(2:4:2)| # of Type C Asci(2:2:2:2)| | | | | | | Tan Spore Color| | | |

5669| 4301| 3976| 13946| 8277| 8277/13946| 4301/13946| 3946/13946| 4301/3976| Gray Spore Color|
| | | | | | | | |
This table represents the number of asci observed as a course. Out of 13,976 asci observed, 8,277 were recombinant. The other 5,669 observed showed no crossing over.

This data from our experiment suggests that crossing over occurs more often than none. In other words, genetic variation is increased within a population of Sordaria.

4:4 No Crossing Over

This cross illustrates the process of when the chromosomes do not cross over. This results in no genetic variation and the asci have a ratio of 4:4 or 4 spores of wild-type and 4 of tan spores.

2:2:2:2 or 2:4:2 Crossing Over

This cross illustrates the process of when the chromosomes do cross over. Crossing over occurs in Prophase I of Meiosis I, which results in the chromosomes having genetic variation. The asci can either have ratios of 2:2:2:2 or 2:4:2.

Crossing Over Frequencies
% Crossing Over= (# of Recombinants/ Total # of Asci )x 100 Individual Crossing Over: (12/26)x100= 46%
Group Crossing Over: (38/70)x100=54%
Section Crossing Over: (86/152)x100= 57%
Course Crossing Over: (8277/13946)=59%

As our asci pool increases the more accurate the crossing over frequencies are, since more asci can be represented in a sample. Our course’s data represents crossing over occurred...
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