14/ human genetics

Question 1

what % of embryos have chromosomal defects

Answer 1

50

Question 2

what % of newborns suffer a congenital disorder

Answer 2

• 5
• includes chromosomal, mitochondrial, single gene, complex - multi factor

Question 3

what proportion of diseases have a genetic element

Answer 3

2/3

Question 4

what % of live births have a chromosomal defect

Answer 4

0.1

Question 5

mitochondrial genome

Answer 5

• own genome
• 2-10 copies of the genome in each mitochondria
• 16.6 kb
• all copies of mtDNA in a cell are the same usually - homoplasmic

Question 6

mitochondrial disease and mutations

Answer 6

• mutation in a copy of mtDNA - mixture of genomes arise, heteroplasmic
• mitochondrial diseases dont follow menelian inheritance
• maternally inherited

Question 7

single gene disorders vs complex diseases

Answer 7

• single gene: disease alleles at single gene, follow medelian inheritance pattern, individually rare but collectively common, high penetrance (deterministic), predictive tests (if you have this mutation, you’ll get this disease). mutations always in coding sequence
• complex disorders: risk alleles at multiple genes - polygenic, no simple pattern of inheritance but runs in families, common, susceptibility not deterministic, lack of reliable tests, environmental influence. often mutation in non-coding region

Question 8

human genome stats: size, coding %, number of coding genes

Answer 8

• 3.2Gb giga bps
• 1.1 - codes proteins
• 20,500 protein encoding genes
• yeast only 6,000, fly 14,000

Question 9

what does ENCODE stand for and what does it do

Answer 9

• the encyclopedia of DNA elements consortium
• international research collaboration
• goal is to build up a comprehensive parts list of functional elements in the human genome
• archived through genomic, functional and bioinformatic approaches
• includes elements that regulate RNA and proteins

Question 10

when was the 1st draft of human genome published, how much did it cost, what did it sequence

Answer 10

• 2001 after 15 yrs
• 3 billion dollars
• whole euchromatic region (92%) minus heterochromatic and repetitive sequences

Question 11

what is next generation sequencing NGS, how long does it take to sequence a human genome, how much does it cost

Answer 11

• all based on sequencing a lot of small fragments of DNA
• dif technologies
• 24hrs, $600

Question 12

examples of single gene disorders

Answer 12

• huntingtons disease - autosomal dominant
• cf - autosomal recessive
• duschenes muscular dystrophy - x chromosome linked