mendelian inheritancein humans

Question 1

pedigree

Answer 1

diagram of genetic features of a family over multiple generations

Question 2

consanguineous mating

Answer 2

incest

Question 3

late on set genetic trait

Answer 3

although gene is present at birth symptoms come in later eg. parkinsons

Question 4

dominant trait genetic disease

Answer 4

passed through generation

vertical pattern; at least one parent and grandparent has disease

Question 5

recessive trait genetic diseases

Answer 5

horizontal pattern
not passed through generations, so grandparents or parents dont necessarily have to have
parents both have to be carriers

Question 6

polygenic trait

Answer 6

traits controlled by two or more genes

exhibits variable expressivity within the population

Question 7

multifactorial

Answer 7

traits controlled by two or more genes and interactions with environment

Question 8

incomplete dominance

Answer 8

hybrid does not represent either pure breeding parent “blend” of both

Question 9

codominance

Answer 9

when phenotypes of both pure breeding parents show equally

Question 10

law of segregation

Answer 10

• cells carry two copies of each gene

- these two copies segregate during gamete formation and two alleles are resorted to each cell

Question 11

blood type

Answer 11

recessive epistasis
- type A make enzyme that adds polusaccharids A onto sugar
type B adds polysaccharid B
type O dont make A nor B enzyme so no polysaccharid

Question 12

alleles

Answer 12

no allele is inheritantly dominant, just in relation to another allele

Question 13

mutations

Answer 13

chance alterations of genetic material arise spontaneously

Question 14

monomorphic

Answer 14

gene with only one common wild type allele

Question 15

polymorphic

Answer 15

genes with more than one common allele

Question 16

pleiotropy

Answer 16

single gene determining # of distinct and unrelated characteristics

Question 17

lethal alleles recessive

Answer 17

arent counted in the ratio so 2:1
homozygous individuals cant make any vital molecule as both are lethal
heterozygous individuals can make 50% normal allele

Question 18

tay sachs disease

Answer 18

new borns deteriorate after 5-6 months due to absense of active lysosomal enzyme and accumulate toxic waste
– can only be carried by heterozygous individuals

Question 19

sickle cell

Answer 19

haemoglobin composed of alpha globin and beta globin polypeptide chains specified for different genes
b globin is normal wild allele that gives rise to 400 mutant alleles

Question 20

genotypic classes

Answer 20

defined by presence or absense of the dominant allele
one present, none present are two classes for one gene
one present, both present, other present, neither present is 4 classes for two genes

Question 21

complemetary gene action

Answer 21

when a phenotype has more than one gene class 
eg to make purple flowers from two white flowers need both genes present a dominant allele A_B_

Question 22

epistasis

Answer 22

effects of an allele at one gene hide effects of alleles to another gene

Question 23

epistatic gene

Answer 23

gene that hides effects of other gene

Question 24

hypoepistatic gene

Answer 24

gene that is masked by another gene

Question 25

recessive epistasis

Answer 25

the gene that masks is recessive

Question 26

dominant epistasis

Answer 26

the gene that masks is dominant

Question 27

development pathway

Answer 27

downstream

Question 28

biosynthetic or biochemical pathway

Answer 28

upstream

Question 29

heterogeneous trait

Answer 29

a trait that can result from a mutation in one of a number of different genes.

when multiple genes code for a process like normal hearing a mutation in any of the gene can still produce same phenotype

Question 30

complementation test

Answer 30

determining wheter a particular phenotyp arises from mutation in the same or separate genes

Question 31

complementation

Answer 31

when off spring of two individuals with mutations express the wild type phenotype
- which indicates that the mutations affected two different genes so normal allele from each parent can be provided which other cant

Question 32

penetrance

Answer 32

how many members of a population show phenotype (complete or incomplete)

Question 33

expressivity

Answer 33

degree or intensity with which a genotype is expressed (variable or unvarying)

Question 34

modifier genes

Answer 34

have a subtle secondary effect by altering phenotype produced by other genes

Question 35

permissive conditions

Answer 35

range of temps where viable

Question 36

restrictive conditions

Answer 36

above the range where lethal

Question 37

human traits characteristics

Answer 37

continuous, polygenic traits that vary over range of values that can be measured

Question 38

discontinuous trait

Answer 38

trait whose phenotypes fall into discrete categories

Question 39

what increases the number of phenotypic classes resulted from a cross

Answer 39

incomplete dominance

codominance

Question 40

redundant genes

Answer 40

genes that specific nearly identical proteins that perform the same function