B04 - Human Genetics at Medizinische Universität Wien

N-glycosidic bond between N of the bases and C1 of the sugar 

Covelnt bonds form between the phosphate that is linked to the 5' carbon of one nucleotide and the 3' carbon of the sugar of the next nucleotide 

amount of DNA in the species haploid genome (= haploid DNA content) 

• Normal count: 23 chromosomes (22 autosome + XX / XY)
• Exception: erythrocytes, megakaryocytes & cancer cells 

Pair of chromosomes - one inherited from the father, the other one from the mother 

• Triploidy: the whole genome gets copied (e.g. 69 XXX, ...) 
• Aneuploidy: only chromosome gets copied (e.g. 47 XY, 45X, ...) 

Gene dosage effect: lower or higher expression off genes encoded on an additional or missing chromosome --> leads to imbalance in the organism 

one randomly chosen X-Chromosome gets inactivated = Barr body; 

Mitochondria & Chloroplasts are descendants from free living cells: the still contain a circular chromosome with a few genes on it 

• 1 circular chromsome with ~ 17kb (containing 37 genes) 
• only maternal inheritance (therefor no crossing over!) 
• mutations in mitochondrial DNA --> LHON, .... 

• 1/3 DNA 
• 1/3 Histones
• 1/3 Non-histone proteins 

• less abundant than histones! 
• for DNA replication, DNA repair, transcription, gene regulation, recombination, topoisomerases, .... 

• group of similar interacting proteins: H2A, H2B, H3, H4, H1 
• rich in arginine & lysine (+) --> good interaction with DNA (-) 
• for coiling up the DNA and regulation of transcription