HUMAN GENETICS L18

Question 1

difficulties in studying human genetics

Answer 1

• few offspring
• long generations
• can’t experiment on humans

Question 2

how to study human genetics

Answer 2

• population studies of large extended families
• analyze matings that have already occurred
• medical attention to human genetic diseases
• “natural experiments”
• DNA sequencing (many generations – extended relatives – genetic basis of similarities and differences)

Question 3

pedigree

Answer 3

• family tree that shows inheritance patterns over several generations
• can determine inheritance pattern (dom or rec)
• based on prevalence and distribution of trait

Question 4

Mendelian inheritance in general

Answer 4

gene – protein – function

defective allele – defective protein or none at all – no function

Question 5

recessively inherited disorders

Answer 5

• autosomal recessive
• dominant allele makes enough protein
• heterozygotes are carriers
  to have the disorder:
• must be homozygous recessive
• 2 copies of defective allele required
• ex. sickle cell

Question 6

dominant inherited disorders

Answer 6

• autosomal dominant
• only one defective allele required
• ex. achondroplasia

Question 7

non-Mendelian inheritance in general

Answer 7

• changes to chromosome number

- can cause disease

Question 8

aneuploidy

Answer 8

• presence of abnormal number of particular chromosome

- extra or missing copy (trisomy or monosomy)

Question 9

XO

Answer 9

• 44 autosomes
• 1 X chromosome
• females

Question 10

XXY

Answer 10

• 44 autosomes
• 2 X, 1 Y chromosome
• male
• Barr bodies

Question 11

XYY

Answer 11

• 44 autosomes
• 1 X, 2 Y
• phenotypically normal
• usually fertile – do not transmit extra Y
• no Barr bodies

Question 12

genomic imprinting

Answer 12

• epigenetics

- DNA methylation (don’t change DNA sequencing)