Lec 14-3

Question 1

Sex can regulate

Answer 1

Autosomal gene
expression

genes located in cytoplasm

Characteristics regulated by maternal genotypes

Question 2

Sex-influenced characteristics

Answer 2

Traits regulated by autosomal genes and mendelian inheritance

but

trait is more readily expressed in one sex

Question 3

In other words

Answer 3

Sex influenced traits have higher penetrance in one sex

Question 4

Goat beards

Answer 4

Autosomal but more strongly expressed in males

Question 5

Sex-limited characteristics

Answer 5

Traits that are regulated by autosomal genes and only expressed in one sex

Question 6

Example of sex-limited characteristics

Answer 6

Cock feathering for domestic chickens

hh cock feather is only in males

Question 7

Male-limited precocious puberty

Answer 7

Males undergoing puberty at a very early age

example of a sex-limited characteristic

Question 8

Sex-limited characteristics can be

Answer 8

Inherited from either parent but only expressed in one sex

Question 9

Nuclear genes

Answer 9

Regulate characteristics

Humans have about 20k genes

Question 10

Mitochondrial genes

Answer 10

Can regulate important characteristics

Only 37 genes in humans

Question 11

Mendelian genetics (principles of segregation and assortment) are based on the assumption that

Answer 11

genes are located on chromosomes in the nucleus

Question 12

Traits that are encoded in mitochondrial genome exhibit

Answer 12

Cytoplasmic inheritance

Question 13

Cytoplasmically inherited traits are present in both

Answer 13

Males and females

Only passed from mothers to children

Reciprocal crosses give different results when cytoplasmic genes are used

Question 14

Cytoplasmically determined traits display extensive

Answer 14

phenotypic
variation

Question 15

Cytoplasmic inheritance

Four-o clocks

Answer 15

Flowering plants that display cytoplasmic inheritance

Some strains have branches that are
different across the plant.
- some branches all green
- some branches all white
- some branches are variegated
(mottled pattern)

green leaves have only wild-type

White have only mutant

variated have both

Question 16

Mitochondrial diseases

Answer 16

Number of rare human diseases involve cytoplasmic inheritance

These diseases are the result of mutations in mitochondrial DNA

Question 17

LHON

Answer 17

People with this have rapid loss of vision in early adulthood

Mitochondrial disease

Question 18

Arthur Boycott

Answer 18

Tried to study snail chirality using mendelian principles of heredity

Found that right handed snail was dominant, but this was not due to the genotype of the individual rather than the individual’s mother

Question 19

Arthur Boycott found

Answer 19

The genetic maternal effect

Question 20

Genetic maternal effect

Answer 20

Phenotype is determined by the genotype of the mother

is NOT cytoplasmic inheritance

Question 21

Genomic imprinting

Answer 21

Differential expression of genetic material depending on whether it is inherited from the male or female

Question 22

Igf2 (insulin-like growth factor) example

Answer 22

progeny receive Igf2 from both parents

maternal is silenced, thus progeny can have only one copy which can lead to low fetal size and growth

Question 23

Genomic imprinting involves

Answer 23

Methylation of the DNA/genes (addition of methyl CH3 group)

Question 24

Genomic imprinting is a type of

Answer 24

epigenetics- some traits are determined by modifications to DNA or chromatin (like DNA methylation)