120
5 Einsatz in der Schule
unambiguously the genetic characteristics of these two
mutations. They must determine:
dominant vs. recessive;
lethal vs. non-lethal;
autosomal vs. sex-linked;
if the two mutations are linked, a map distance.
Virtual FlyLab can be used to illustrate several genetic principles.
For example, exercises can be designed to demonstrate:
monhybrid, dihybrid, and trihybrid Mendelian ratios;
the modification of Mendelian ratios due to sex-linkage;
the modification of Mendelian ratios due to lethality;
the modification of Mendelian ratios due to epistasis;
how to map genes on a chromosome using single and
double crossover frequencies;
how to locate genes to a chromosome using "balanced
marker" mutations;
the empirical relationship between actual map distance and
crossover frequencies as genes become further apart on a
chromosome.
Wie ein solches Experiment aussehen kann, zeigen die folgenden
Bilder. Dabei werden zwei Fruchtfliegen gepaart. Im Beispiel haben
diese 14 verschiedene direkte Nachkommen. Sämtliche genetischen
Codes und Abkürzungen sind auf W3 erklärt.
