making punnett predictions
TRANSCRIPT
MAKING PUNNETT PREDICTIONS
http://www.exploratorium.edu/exhibits/mutant_flies/mutant_flies.html
m m
+
+
+m +m
+m +m
IF GENE is AUTOSOMAL and RECESSIVE TO +MALES:FEMALES 1:1
+ m
+
m
++ +m
+m mm
http://www.exploratorium.edu/exhibits/mutant_flies/curly-wings.gif
F1
All = +m (wildtype)
F2
¼ = ++ 75% wildtype½ = +m¼ = mm 25% mutant 3:1
M M
+
+
+M +M
+M +M
IF GENE is AUTOSOMAL and DOMINANT TO +MALES:FEMALES 1:1
+ M
+
M
++ +M
+M MM
F1
All = +M (mutant)
F2¼ = ++ 25% wildtype½ = +M¼ = MM 75% mutant 1:3
Y yy
y
Yy yy
Yy yy
IF GENE is LETHAL (YY)(Can’t cross pure dominant)Males:females 1:1
Y y
Y
y
YY Yy
Yy yy
X
F1 50% = Yellow50% = grey
F2
¼ = YY (lethal) ½ = Yy 2/3 yellow¼ = yy 1/3 grey 2:1 ratio
F1
F2
X+ y
Xm
Xm
X+Xm Xmy
X+Xm Xmy
IF GENE is X-linked recessiveDifferent pattern if gene is inherited from mom or dadMutant mom X wild type dad
Xm y
X+
Xm
50% normal females 50% mutant males
X+Xm X+y
XmXm Xmy
When using Virtual fly labChoose ignore sex and see if it changes the ratios
25% normal females25% mutant females 25% mutant males25% normal males
F1 F1
Xm y
X+
X+
X+Xm X+y
X+Xm X+y
IF GENE is X-linked recessiveDifferent pattern if gene is inherited from mom or dadWild type mom X mutant dad
X+ y
X+
Xm
50% normal females 50% normal males
X+Xm Xmy
X+Xm Xmy
When using Virtual fly labChoose ignore sex and see if it changes the ratios
50% normal females 50% mutant males
F1 F2
X+ y
XM
XM
X+XM XMy
X+XM XMy
IF GENE is X-linked dominantMUTANT MOM X WILD TYPE DAD
XM y
X+
XM
50% mutant females50% mutant males
X+XM X+y
XMXM XMy
When using Virtual fly labChoose ignore sex and see if it changes the ratios
F1 F2
50% mutant females 25% wild type males25% mutant males
XM y
X+
X+
X+XM X+y
X+XM X+y
IF GENE is X-linked dominantWILD TYPE MOM X MUTANT DAD
X+ y
X+
XM
50% mutant females 50% normal males
X+X+ X+y
X+XM XMy
When using Virtual fly labChoose ignore sex and see if it changes the ratios
25% wild type females25% mutant females25% wild type males25% mutant males
F1F2
GENETIC ABBREVIATIONSDOMINANT MUTATIONS: first letter = capitalized. EX: sternopleural bristles= Sp
RECESSIVE MUTATIONS = lower caseEX: mahogany eyes = mah
normal "wild type" version of the gene = same abbreviation as mutant with a "+" superscriptFor example, Sp+ and mah+.
Sometimes, when the meaning is obvious, "+" by itself is usedEX: heterozygote genotypes: +/Sp and +/mah.
VIRTUAL FLY LAB DOESN’T FOLLOW THIS PROTOCOL:You need to explore and figure out whether it is dominant or recessive.