Lecture 45

Question 1

What is hybridization?

Answer 1

Cross between 2 different species

Question 2

Lemon x orange

Answer 2

meyer lemon

Question 3

Tangerine x pomelo grapefruit

Answer 3

tangelo

Question 4

Mandarin x orange

Answer 4

clementine

Question 5

What is a mule? What are the chromosome numbers of mules and its two hybridized parents?

Answer 5

female horse x male donkey

horses 2n = 64
donkeys 2n = 62
mules 2n = 63

Question 6

When did hybridization occur in humans?

Answer 6

60 000 years ago between homo sapiens and neanderthals

Question 7

What is polyploidy?

What are the names for 3n, 4n, 6n, 8n

Answer 7

organisms with 3 or more sets of chromosomes

triploid = 3n
tetraploid = 4n
hexaploid = 6n
octoploid = 8n

Question 8

What is autopolploid?

Allopolyploid?

Answer 8

copies from the same species

copies from different species

Question 9

What ploidy is pasta (durum) wheat? Are they autopolyploid or allopolyploid?

Answer 9

tetraploids (each adult cell has 4 copies of each chromosome and thus 4 copies of each gene)

allotetraploid (two diploid species spontaneously hybridized to become a new allo-tetraploid species (triticum monoccum + triticum searsii = triticum turgidum durum) (larger + hardy_

Question 10

What are some properties of tetraploid plants?

Answer 10

viable (mitosis works)

fertile (meiosis pairs correctly)

Question 11

What ploidy are bananas?

Answer 11

triploidy (each adult cell has 3 copies of each chromosome and thus 3 copies of each gene)

Question 12

What are the origins of Cavendish bananas?

Answer 12

one diploid species was artificially made into an auto-triploid species (musa acuminata + musa acuminata = cavendish bananas)

Question 13

What are the origins of plantain bananas?

Answer 13

two diploid species were artifically made into an allo-triploid species (musa acuminata + musa balbisiana = plantain bananas)

Question 14

What are characteristics of triploid plants?

Answer 14

viable (mitosis works)
sterile (meiosis fails, no pairing partners)

Question 15

Why are bananas seedless?

Answer 15

because meiosis fails, cultivated bananas don’t have seeds

Question 16

How do farmers grow new banana trees?

Answer 16

From pieces of roots (vegetative)

Question 17

How does polyploidy in humans occur?

Are they viable?

Answer 17

double fertilization

non viable because human development cannot tolerate polyploidy

Question 18

Why are mules sterile?

Answer 18

chromosomes can’t pair in meiosis