Lecture 5 - Post Midterm 1 Flashcards
terminal deletion
the chrom breaks in 1 place
now you have two pieces
the piece w/o a centromere is lost n degraded
intersitial deletion
the chrom breaks in two places,
now u have 3 pieces
the ends rejoin
the middle part is lost n degraded
what is the phenotypic consequence of deletions?
it depends on the size of lost peices n whether the lost parts contained important genes for dvl n func
Cri-du-chat syndrome
deletion on short arm of chrom 5
Phenotype seen even w only one abnormal copy of chrom
Mental deficiencies, facial anomalies, catlike cry
which is more harmful: deletions or duplications?
deletions
why may deletions n duplications occur?
if crossing over happens incorrectly btwn homologous chroms
why may misallightment during crossing over of homologous chroms occur?
by pairing at repetitive sequences
what is the result of incorrect crossing over? how many deletions? how many duplications?
one chromosome with a deletion and one with a duplication
what is the phenotypic consequence of duplications?
Most small duplications don’t have phenotypic effect
why r duplications important?
for adding genes to a species’ chromosomes during evolution
what types of translocations r there?
reciprocal translocations
Robertsonian Translocations
reciprocal translocations
two double strand breaks, each on a different, non-homologous chromosome
one region from one chromosome is swapped with a region from another chromosome.
Robertsonian Translocations
large translocations involving chromosomes with very short p arms
Typically, one of the affected chromosomes is so small that it lost
what happens if a Robertsonian Translocations occurs on chrom 21?
downs syndrome may result
what r human chroms w v short p arms?
13, 14, 15, 21, 22
