In genetics, all of the genes on a single chromosome. They are inherited as a group; that is, during cell division they act and move as a unit rather than independently.
The existence of linkage groups is the reason some traits do not comply with Mendel's
Linkage group
The law of "Independent Assortment".
It is also possible for some of your children to inherit new combinations called "re-combinants" from you.
the principle applies only if genes are located on different chromosomes.
The second Mendelian law
cross
N2 males X dpy-13 hermaphrodites
-->
dpy-13/+ males X RW7000 hermaphrodites
-->
two classes of sperms and one class of oocytes
dpy-13 and WT WT 1
-->
two classes of hermaphrodite progeny
dpy-13 sperm. WT sperm
WT 1 oocytes. WT 1 oocytes
PCR
If you pick up Dpy worms to do PCR, 75% of them will amplify marker 2, but none of them will show the presence of marker 1.
crossing over
Process in which homologous chromosomes exchange portions of their chromatids during meiosis.
When does crossing over occur?
prophase I of meiosis
Probability
P(A ? B): Probability that event A and/or event B occurs.This is also known as the probability of the union of A and B.P
(A ? B): Probability that event A and event B both occur.This is also known as the probability of the intersection of A and B.
conclusion
If dpy-13 mutation is on the chromosome where marker 1 localizes, the chance to detect thepresence of marker 1 in Dpy worms is around 0.75 X recombination frequencybetween dpy-13 and marker 1 .The chance to detect the presence of marker 2 in Dpy worms is
what causes dip-13 mutant?
a deletion aprox 30 bp