L.2 Flashcards
What is the chromatin structure?
Chromatin ——>nucleosome —-> 1) histone amplification 2) DNA methylation
Explain Euchromatin ?
Active , unmethylated cytosines and acetylated histones
Explain Heterochromatine ?
Condensed , methylated cytosine and deacetylated histones
Conventional cytogenetics can detect chromosomal changes size what ?
Less than 5 Mb
What are the two categories of chromosomal structural abnormalities?
Balanced and unbalanced
How can u differentiate between balanced and unbalanced chromosomal changes?
Balanced will not gain or loss genetic content
Unbalanced will gain and loss // // //
Structural chromosomal abnormalities is inheritable if it’s where ?
Germ line
What are the two types of deletion ?
Large deletion ( > 5Mb)
Small deletion ( < 2Mb )
Give examples for large and small deletion ?
Large : cri-du-chat syndrome del of chr 5
Small : smith-magennis syndrome del of chr 17p11.2
What are the types of chromosomal structural abnormalities?
Deletion
Duplication
Inversion
Translocation
What happen in inversion ?
Two breaks occur at the chromosome and then this part of the Chr rotate in 180 degree before re-joining
Example of inversion
Haemophilia A gene 8 Chr 22
What are the two types of translocation
Reciprocal translocation
Robertsonian translocation
What is reciprocal translocation
When two chr swap non-homologous sections
Does the n of chr and the genetic content chain in Reciprocal translocation
No stay the same so it’s balanced