Principle of Gen, Seidler

Question 1

Genes

Answer 1

segment of DNA in chromosome

Question 2

Locus (loci)

Answer 2

where gene occupies on chromosome

Question 3

Telomere

Answer 3

region at end of chromosome for stability

Question 4

Somatic Cells

Answer 4

diploid

differentiated, have a specific destination tissue

Question 5

Stem cells

Answer 5

undifferentiated cells that can divide into 2 diploid cells

not sure what they will be yet

Question 6

Homologous chromosomes

Answer 6

pair of chromosomes

Question 7

Mosaicism

Answer 7

cells from patient have a different genotype (and karyotype)

ex: downs syndrome, klinefelter syndrome, turner syndrome,

Question 8

Lyonization (X-inactivation)

Answer 8

random choice of which X chromosome is to be inactivated

Question 9

Cell Cycle

Answer 9

Interphase-
G1: Cell growth and differentiation

S: synthesis of DNA, duplication of chromosomes

G2: cell growth and prep for cell division

Mitotic cell division
prophase, metaphase, anaphase, telophase, cytokinesis

Question 10

Non-disjunction

Answer 10

failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during divison

Question 11

Autosomes

Answer 11

chromosomes codon in both genders, one from each parent

Question 12

Meiosis genetic diversity

Answer 12

Random segregation of homologs

Cross-over exchange

Question 13

Aneuploid

Answer 13

cells with abnormal chromosome number
    Trisomy 21: (down syndrome) 
     additional 21 (70% in Meiosis 1)

Question 14

Down Syndrome

Answer 14

Trisomy type: 47, XX +21

Robertsonian Translocation: 46, XX der(14:21) +21

Mosaic Type: 46,XX/47,XX+21

Question 15

Klinefelter Syndrome

Answer 15

47XXY compared to 46XY

extra X chromosome, boy has girl features (lack testosterone, breast growth, little hair)

Question 16

Turner Syndrome

Answer 16

45X0 compared to 46XX

girl lacking X chromosome
delayed puberty, small stature…

Question 17

Uniparental Disomy

Answer 17

2 chromosomes from the same parent have parent-specific imprinting = no gene product

ex: Prader Willi, Angelman, Beckwith-Wiedemann

Question 18

Prader Willi Syndrome

Answer 18

chromosome 15

paternal chromosome is deleted
get both 15’s from mother

Question 19

Angelman Syndrome

Answer 19

chromosome 15

maternal chromosome is deleted
get both 15’s from father

Question 20

Beckwith-Wiedemann

Answer 20

chromosome 11 uniparental disomy

Question 21

Genetic Mechanisms of Disease

Answer 21

Loss of Function = Duchenne Muscular Dystrophy
Gain of Function = Cancer
Protein Alteration = Sickle Cell Anemia

Question 22

Cystic Fibrosis

Answer 22

individuals with distinct genotypes can have single phenotype (different classes result in CF)

Question 23

PKU

Answer 23

individuals with same genotype can have multiple phenotypes

very specific defect
Tyr exposure
Phe removal/transportation etc…

Question 24

Autosomal Dominant

Answer 24

pedigree shows trait in every generation

only 1 allele for trait is needed, 50%

Postaxial Polydactly

Question 25

Autosomal Recessive

Answer 25

consanguinity more likely to cause occurrence 2 copies of allele is needed for phenotype, 25% Tyrosinase-negative/deficiency Albinism

Question 26

X-linked Recessive

Answer 26

unaffected males don't transmit, never carriers female carriers can transmit 50% sons and daughters all daughters of affected males are heterozygous carriers Duchenne Muscular Dystrophy

Question 27

X-linked Dominant

Answer 27

rare, no carriers affected males transmit 100% only to females Hypophosphatemia leads to Rickets in children soft bone, bad absorption of Ca and phosphate

Question 28

Penetrance

Answer 28

Frequency that a gene manifests itself some cases = 100% some are less

Question 29

Reduced penetrance

Answer 29

Retinoblastoma (also autosomal dominant) phenotype occurs in 90% of individuals inheriting the genetic defect (90% penetrance)

Question 30

Variable expressivity

Answer 30

the range of phenotypes that vary between individuals of a specific genotype Neurofibromatosis tumor like growths (Cafe-au-laits spots)

Question 31

Locus Heterogenity

Answer 31

single disorder, trait, or pattern of traits caused by mutations in genes at different chromosome loci Osteogenesis Imperfecta brittle bone disease mutations in 7 and 17 loci, either produces this disease

Question 32

Gene Frequency (Allele Frequency)

Answer 32

the proportions of each allele in a population A or a

Question 33

Genotype frequency

Answer 33

the proportions of each genotype in a population AA vs Aa vs aa

Question 34

Hardy Weinberg Principle

Answer 34

p2 (squared) = AA frequency q2 (squared) = aa frequency 2pq = Aa frequency p + q = 1

Question 35

Multifactorial Disease

Answer 35

caused by simultaneous influence of multiple genetic and environmental factors