Week 5: L1 RECOMBINATION Flashcards
What is recombination?
breaking and rejoining in new combinations
What are the 2 types of recombination?
homologous and site-specific
What is an homologous chromosome?
Two DNA molecules which are virtually identical DNA sequences
Where does DNA recombination occur in homologous chromosomes?
anywhere along the region of homology
What is an important process where genetic recombination occurs?
meiosis
What is the difference between meiosis and mitosis first stage?
Mitosis: diploid daughters cells identical to parents
Meiosis: Haploid daughter cells not identical to parent or each other
What happens to Meiosis cells at stage 2 meiosis?
Cell division again and now 1 chromosome from dad and 1 from mum = haploid
When does recombination occur between sister chromatids?
During metaphase and meiosis 1 when homologous chromosomes line up (XX at equator)
Where does the crossing-over take place?
chiasmata
How is homology identified in chromosomes?
entire genome has to be searched and aligned.
What can genetic recombination test?
test for that homology
What facilities for the searching of homologous sequences?
cohesin
What are cohesins?
a composite ring like molecule that hold sister chromatids together.
search for homologous sequences
Where else does recombination occur?
in bacteria too E.coli
What is transducing phage?
pick up chromosomal DNA on bacterial chromosome e.g. plasmid.
Can recombine with the host chromosome.
