VARIATIONS TO MENDEL'S LAW OF GENETICS

Question 1

Affects both sexes and appears every generation

Answer 1

Autosomal Dominant

Question 2

Affects both sexes and can skip generations through carriers, who do not have symptoms

Answer 2

Autosomal Recessive

Question 3

• Mixture of both traits of both parents
• Heterozygous phenotype is intermediate between those of the two homozygotes
• Mendel observed that the cross of a plant with red flowers and one with white flowers gave progeny that were pink, an intermediate phenotype

Answer 3

Incomplete Dominance

Question 4

• Heterozygous phenotype results from the expression of both alleles
• In codominance, neither allele is
  recessive and the phenotypes of both alleles are expressed
• Best explains the inheritance of Blood Type
• Walang recessive, both namamana yung dominant traits

Answer 4

Codominance

Question 5

• Is a phenomenon in which an individual possess cells with genetic differences from the other cells in the body
• Other cells in the body are normal while one or more cell lines are mutated
• 2 traits ang lalabas

Answer 5

Mosaicism

Question 6

• Mosaicism in Somatic cells
• Post zygotic mutation, not the rest of the body is affected

Answer 6

Constitutional Mosaicism

Question 7

• Mosaicism in Sex cells
• Has two populations of cells in the gonads (testes or ovaries), one population of cells containing the usual genetic complement whilst the other contains a DNA mutation or chromosome anomaly

Answer 7

Germline Mosaicism

Question 8

genetic disorder that prevents the body from building strong bones

Answer 8

brittle bone disease

Question 9

Mutations in the dystrophin gene lead to progressive muscle fiber degeneration and weakness

Answer 9

Duchenne muscular dystrophy

Question 10

• Triplet repeats are short tandem repeats with base pair (trinucleotide) repeating units
• Eg. CAGCAGGCAG…CAGCGCCGCCGCCG…CCG
• Group of human diseases, which are a result of an abnormal expansion of repetitive sequences and primarily affect the nervous system.
• These occur during various stages of human development.

Answer 10

Trinucleotide Repeat Disorder

Question 11

examples of trinucleotide repeat disorders

Answer 11

• fragile-x syndrome (CGG)
• huntington’s disease (CAG)
• friedrich ataxia (GAA)
• myotinic dystrophy (CTG)

Question 12

• Worsening of mutation in successive generations
• Characterized by progressively earlier onset and increased severity of disease
• As gene is passed from generation to generation, expansion occurs
• The number of triplet repeats increases

Answer 12

Anticipation

Question 13

• Most common cause of inherited intellectual disability
• Most commonly known genetic cause of Autism

Answer 13

Fragile X Syndrome

Question 14

Fragile site at position ?

Answer 14

Xq27.3 gene FMR1

Question 15

FMR1 gene encodes ?

Answer 15

fragile X mental retardation protein

Question 16

• An autosomal dominant, late-onset neurodegenerative disorder

Answer 16

Huntington Disease

Question 17

part of the brain affected in Huntington Disease

Answer 17

basal ganglia

Question 18

reason for Huntington Disease

Answer 18

an increase in the number of repeated Glutamine-encoding CAG codons in exon 1 of the HD gene

Question 19

HD gene

Answer 19

4p16.3

Question 20

Normal CAG copies

Answer 20

10-27 copies

Question 21

Mutable CAG copies

Answer 21

28-35

Question 22

Reduced penetrance CAG copies

Answer 22

36-39

Question 23

Associated with disease CAG copies

Answer 23

> 40

Question 24

HD mean age of onset

Answer 24

35-44 yrs old

Question 25

Median surival time of HD after the onset of symptoms

Answer 25

15-18 years

Question 26

Symptoms of HD in the first few years

Answer 26

• Mood disturbances
• Cognitive deficits
• Clumsiness
• Impairment of voluntary movement

Question 27

Next stage of HD

Answer 27

– Slurred speech (dysarthria)
– Hyperreflexia
– Chorea
– Gait abnormalities
– Behavioral disturbance:
– Aggression

Question 28

Advance stage of the Huntington disease:

Answer 28

– Bradykinesia
– Rigidity
– Dementia
– Dystonia
– Dysphagia

Question 29

Late stages of HD

Answer 29

– Weight loss
– Sleep disturbance
– Incontinence

Question 30

• Some traits are transmitted through cytoplasm and organelles since these also carry DNA
• Called Cytoplasmic Inheritance or Extranuclear Inheritance
• Inherited with the egg cytoplasm from the mother

Answer 30

Maternal Inheritance

Question 31

• Example of Maternal inheritance
• Have their own genomes
• Produce ATP through Oxidative Phosphorylation
• Called 47th chromosome
• Have distinct DNA, called mtDNA

Answer 31

Mitochondria

Question 32

• Small double-stranded circular molecule that contains 37 genes:
• 22 mitochondrial tRNA
• 2 mitochondrial rRNA
• 13 polypeptides

Answer 32

Mitochondrial DNA

Question 33

2 Factors in Maternal Inheritance

Answer 33

1. Inheritance pattern of the organelle
2. Number of copies of organelle chromosomes in the cell

Question 34

The genotype of the offspring is determined entirely by the parent that contributes the cytoplasmic organelle which is the ?

Answer 34

Female

Question 35

LHON

Answer 35

Leber’s Hereditary Optic Neuropathy

Question 36

MELAS

Answer 36

Mitochondrial Encephalopathy, Lactic Acidosis, and strokelike episodes

Question 37

MERFF

Answer 37

Myoclonic epilepsy, Ragged Red fibers in muscle. Ataxia, Sensorineural Deafness