Lect 6 Flashcards
Karyotyping is
The characterization of numbers size morphology of a set of chromosomes
Karyotyping aid in
No. Of chromosomes
Position of centromere
No. And position of 2ndry restrictions and banding patterns
Relation between chromosomes and amount of DNA and organism complexity
Interspecific vs intraspecific variation
Cytogenetically different species
Individuals of the same species
What is polymorphism
Cause
Variation in DNA seq among individuals of a species
Numerical or structural abnormalities
Comparative analysis of karyotypes in related species
Autamorphies> characters exclusive to each species
Synapomorphies>charecters common for all
When DNA changes it has … Significance
Like… And ….
Evolutionary
Anagenesis> gradual transformation from 1 species to another, introducing new characters that replace the old ones
Cladogenesis> 1 species divided into 2 by reproductive isolation mechanisms, each species keeps its exclusive charecters
What is reproductive isolation
Meaning that 2 species cant reproduce together or no offspring or sterile
1 character if….. can be transmitted with normsl karyotype
Can have different…. Due to ……of a …and …to progeny
Advantegous
Forms
Structural/ arrangement alternatives
Chromosome
Transmitted
Euploidy is the same as
Polyploidy
What is transposition
Translocation in the same chromosome
Structural changes are recognised by
..
Their effect
Affecting chromosome morphology
Change in markers position(centromere, 2ndry construction, banding pattern)
When karyotypically stable the…are
..
Intra and interspecific chromosomes variation
Small
Some species are morphologically identical but..
Have strong inter and intraspecific variation
How to identify polymorphism
Chromosome no.
Karyotype morphology
Pattern variation
Location of NOR
amount and location of repetitive seq
Repetitive seq identified by….
Allo and autopolyploidy by….
FISH
GISH
Allo polyploidy
Autopolyploidy
From different species
From same organism
2n
N
X
Somatic cells chromosome no.
Gametic no. Of chromosomes
Basic no., no. Of chromosome sets of an individual
What are prochromosomes
Formed during prophase
Karyotypic analysis
Direct >. Size of metaphase plate is proportional to no. Of chromosomes
No. Of heterochromatic segments in interphase and prochromosomes in prophase and no. Of nucleoli is prop to no. Of genomes
Indirect> nucleus size is proportional to Dna size and no. Of chromosomes
Too many small chromosomes is hard to detect…..what method usef
Aneuploidy
Metaphase plate
Disadvantages of direct method
Instability of heterochromatin
Nucleolar fusion
Chromosomes size
Micro chromosomes size
Giant
5-6 um
0.5 um
10 um
DNA amount is predicted by
Amount of light absorbed after feulgen stain
Why karyotypic analysis
Separation and classification of species, cytotaxonomy
Reforming phylogenic trees and evolutionary studies
Evolutionary analysis
karyotyping identifies
karyotypic
polymorphism, interspecific and intraspecific cytogenetic variation and
evolution.
chromosomal alterations can be
advantageous, disadvantageous, or neutral.
karyotypic changes
numerical>cause significant effects
structural>recognized when they affect chromosome morphology such as centromere position
2n=…or…
2
1260
chromosomal alterations are..
unprogrammed variations
eukaryotic chromosomes can differ in….
size-shape-composition
phyligenetic relationships are defined by
chromosome differences between organisms
Allium roseum L.
polymorphic species with 12 taxa
chromosome size, there is also variation of
1.6 μm to 20 μm
in
different species of gymnosperms
