lecture 9

Question 1

what influences phenotypic characters ?

Answer 1

many different genes and their products

Question 2

gene interaction

Answer 2

several genes influence a particular characteristic

Question 3

what does the cellular function of numerous gene products contribute to?

Answer 3

the development of common phenotypes

Question 4

epistasis

Answer 4

interaction of genes that are not alleles; suppression of the effect of one such gene by another

Question 5

is epistasis similar or different from dominance and recessiveness

Answer 5

different

Question 6

what is the bombay phenotype?

Answer 6

a rare recessive mutation at locus that is from an incomplete formed H substance: causes different phenotype for blood type

Question 7

dominant epistasis

Answer 7

dominant allele at one loci masks an allele at a second loci

Question 8

recessive epistasis

Answer 8

when the homozygous recessive gene masks the “dominant” allele

Question 9

complementation analyses

Answer 9

when two strains of an organism with different homozygous recessive mutations that produce the same mutant produce off-spring with the WT phenotype

Question 10

what are the three possible outcomes if a combination of two genomes containing different recessive mutations yield a mutant phenotype?

Answer 10

1. mutations occur in the same gene
2. one mutation affects the expression of another
3. one mutation may result in an inhibitory product

Question 11

pleiotropy

Answer 11

expression of a single gene has multiple phenotypic effects

Question 12

what’s an example of pleiotropy?

Answer 12

marfan syndrome- an autosomal dominant mutation in gene encoding connective tissue protei fibrillin

Question 13

what influences phenotypic expression?

Answer 13

environment and genotype

Question 14

do gene products function in different ways within the cell?

Answer 14

yes

Question 15

penetrance

Answer 15

percentage of expression of mutant genotype in population

Question 16

expressivity

Answer 16

range of expression of mutant phenotype

Question 17

what type of mutation is the eyeless mutation in drosophila?

Answer 17

homozygous recessive

Question 18

what else can influence gene expression

Answer 18

physical location in relation to other genetic material

Question 19

what modifies expression?

Answer 19

translocation or inversion

Question 20

what does physical location impact gene expression?

Answer 20

euchromatin can become heterochromatin or vice versa

Question 21

in conditional mutations, what can effect phenotype?

Answer 21

temperature

Question 22

what are examples of conditional mutations?

Answer 22

evening primrose, Siamese cats, and Himalayan rabbits

Question 23

extranuclear inheritance

Answer 23

vary from traditional biparental inheritance of nuclear genes

Question 24

organelle heredity

Answer 24

organism’s phenotype is affected by genes in the mitochondria and the chloroplasts

Question 25

what is the material effect?

Answer 25

an organism’s phenotype is determined by genetic information expressed in maternal gamete

Question 26

what is organelle heredity?

Answer 26

inheritance patterns related to chloroplast and mitochondrial function

Question 27

what pattern of inheritance is organelle heredity?

Answer 27

extranuclear

Question 28

how is organelle heredity transmitted from the maternal parent?

Answer 28

ooplasm

Question 29

heteroplasmy

Answer 29

the cell may or may not have mutant genes in the organelles but the phenotype may not be revealed; more than one type of organellar genome

Question 30

mitochondrial mutations

Answer 30

DNA found in human mitochondria completely sequenced

Question 31

what must the mitochondrial gene product include?

Answer 31

13 proteins (unless aerobic cellular respiration), 22 transfer RNAs (for translation), and 2 ribosomal RNAs (for translation)

Question 32

what does MERRF stand for?

Answer 32

Myoclonic epilepsy and ragged-red fiber disease

Question 33

what is MERRF?

Answer 33

the gene encoding tRNAlys, it interferes with translation which leads to disorders

Question 34

what happens to cells that are affected by MERRF?

Answer 34

exhibit heteroplasmy; they contain a mixture of normal and abnormal mitochondria