TETRAD ANALYSIS IN FUNGI Image removed to due to copyright considerations. THE PRODUCTS OF A SINGLE MEIOSIS ARE PACKAGED IN A SAC (ASCUS)
TETRAD ANALYSIS IN FUNGI Image removed to due to copyright considerations. THE PRODUCTS OF A SINGLE MEIOSIS ARE PACKAGED IN A SAC (ASCUS)
THE PRODUCTS OF A SINGLE MEIOSIS A a Haploid X A Diploid A 1st division a Meiosis Image removed to due to copyright considerations
A A a a THE PRODUCTS OF A SINGLE MEIOSIS A a Haploid Diploid 1st division Meiosis X a A A a a A Image removed to due to copyright considerations. A a a A
Mendel 1.Segregation:Equal numbers of A and a .The phenotype resulting from a mutation in a single gene will segregate exactly 2A 2a. Question in Tetradspeak: Does the phenotype segregate2:2? Yes.A and a are alleles of a single gene
Mendel 1. Segregation: Equal numbers of A and a •The phenotype resulting from a mutation in a single gene will segregate exactly 2A : 2a. •Question in Tetradspeak: Does the phenotype segregate2:2? Yes. A and a are alleles of a single gene
HOW DO WE KNOW WHETHER TWO GENES ARE LINKED? A B X a b ● B b B a or B B Parental Non-Parental AB Ditype Ab Ditype AB (PD) Ab (NPD) a b a B a b a B
HOW DO WE KNOW WHETHER TWO GENES ARE LINKED ? X a b A B A A a a B B b b A B A B a b a b B B b A b A a a or A b A b a B a B Parental Ditype (PD) Non-Parental Ditype (NPD)
How do you determine linkage? You cross AB x ab and find in 100 tetrads: 48 PD 52 NPD Are A and B linked?
How do you determine linkage? You cross AB x ab and find in 100 tetrads: 48 PD 52 NPD Are A and B linked?
Mendel 1.Segregation:Equal numbers of A and a .The phenotype resulting from a mutation in a single gene will segregate exactly 2A:2a. .Question in Tetradspeak: Does the phenotype segregate 2:2? Yes.A and a are alleles of a single gene. 2.Independent Assortment(linkage):AB x ab .Tetradspeak:Are PD=NPD Yes“ "No Two genes are unlinked Two genes are linked
Mendel 1. Segregation: Equal numbers of A and a •The phenotype resulting from a mutation in a single gene will segregate exactly 2A : 2a. •Question in Tetradspeak: Does the phenotype segregate 2:2? Yes. A and a are alleles of a single gene. 2. Independent Assortment (linkage): AB x ab •Tetradspeak: Are PD = NPD Yes No Two genes are unlinked Two genes are linked
Independent Assortment (linkage):AB x ab .Tetradspeak:Are PD=NPD Two genes are unlinked Two genes are linked
Independent Assortment (linkage): AB x ab •Tetradspeak: Are PD = NPD Two genes are unlinked Two genes are linked
Complete Linkage of Two Genes ●AB X ●ab AB AB ab Parental ditype AB AB AB AB ab ab ab ab
Complete Linkage of Two Genes AB X ab AB AB ab ab AB AB ab ab Parental ditype AB AB ab ab
The Products of a Single Crossover ●A B X ● a b B AB Parental B Ab Recombinant a b aB Recombinant b ab Parental TETRATYPE
The Products of a Single Crossover A B a b X A B AB Parental A B Ab Recombinant a b aB Recombinant a b ab Parental X TETRATYPE
2.Independent Assortment(linkage):AB x ab .Tetradspeak:Are PD=NPD Yes No Two genes are unlinked Two genes are linked TETRATYPE? Yes NO 100%linked Map Distance centiMorgans 1/2TT TOTAL
2. Independent Assortment (linkage): AB x ab •Tetradspeak: Are PD = NPD Yes No Two genes are unlinked Two genes are linked TETRATYPE? Yes NO 100% linked Map Distance = 1/2 TT centiMorgans TOTAL