Transmission Genetics Part 2

Question 1

multiple alleles

Answer 1

more than 2 alleles exist for a single gene

• an individual only has 2 copies of each gene, one from each parent
• ex. blood type, rh factor, galactosemia, hlas

Question 2

galactosemia

Answer 2

• recessive
• body cannot process galactose
• 3 alleles

Question 3

HLAS

Answer 3

human leukocyte antigen complex which means that each gene contains hundreds of alleles

Question 4

Codominance

Answer 4

• two different alleles of a gene have equal expression in the phenotype
• ex. blood types and glycoproteins
• polka dots

Question 5

variable expression

Answer 5

age of onset which is the time when signs and symptoms are first evident
-ex. cancers, hypertension

Question 6

incomplete dominance

Answer 6

• phenotype is heterozygous all the way
• pink flowers
• ex. sickle cell carriers, familal hyypercholesterolemia

Question 7

pentrance

Answer 7

dominant gene is present but is not expressed

-ex. dimples

Question 8

expressivity

Answer 8

how much or degree of phenotypic expression

-ex. polydactyl and dimples

Question 9

genetic heterogeneity

Answer 9

one phenotype from various genetic causes

-ex. muscular dystrphy, dementia, hemophilia

Question 10

phenocopy

Answer 10

non genetic condition has similar signs and symptoms to genetic condition
-ex. head trauma and parkingsons or stroke

Question 11

ecogenetics

Answer 11

interaction of the environment with a gene by changing the genes nucleotides which can cause a new mutation causing a difference in the phenotype

Question 12

epigenetic

Answer 12

a change in the gene’s function that occurs without a change in the DNA sequence but causes a change in the phenotype

• ex. maternal stress during pregnancy causes a decreased masculation of a male child
• prader willi and angelmans

Question 13

prader willi

Answer 13

-dominant
exceptionally high levels of growth because of increased ghrelin which causes need to eat
-decreased muscle tone, low IQ
-dad genetic error

Question 14

angelmans

Answer 14

• very happy, non smooth movement, puppet, low IQ

- mom genetic error

Question 15

pharmacogenetics

Answer 15

individuals reactions to medications

Question 16

linked genes

Answer 16

• genes on the same chromosomes

- genes do not always independently assort and tend to travel together on the same chromosome

Question 17

sex linked genes

Answer 17

• females two X cs are inherited

- males cs genes are hemizygous so all genes on X and Y chromosomes are expressed either dominant or recessive.

Question 18

x linked genes

Answer 18

• females can carry a recessive x linked gene in the heterozygous state
• father can pass genes on to daughter but not to the son
• males express x linked traits more oftern and they cannot carry sex linked traits

Question 19

Few bad dominant disorders

Answer 19

• hypophosphatemia which causes bone curvature

- hypertrichosis- excessive hariness

Question 20

hypophosphatemia

Answer 20

causes bone curvature

-domiant

Question 21

hypertrichosis

Answer 21

excessive hairiness

-dominant

Question 22

hemophilia

Answer 22

• recessive

- blood clotting

Question 23

lesch nyhan syndrome

Answer 23

• recessive

- build up of uric acid which causes spastic movement like uncontrolled chewing

Question 24

muscular dystrophy

Answer 24

• recessive

- progresive weakness of muscle mass

Question 25

G-P-PD

Answer 25

• recessive

- defiency causes RBC lysis

Question 26

red green color defiect

Answer 26

-recessive

Question 27

Y linked genes

Answer 27

• gene passes from father to son w/o changes or mutation
• few genes are linked to the Y chromosome
• ex. HY cell antigen and SRY gene for the organ reciept

Question 28

Hardy-Weinberg Law

Answer 28

rules for application

• allele frequencies must remain constant
• large population must exsist
• mating must be random
• p2+2pq+q2=1