ppt 5

Question 1

were working with
several traits in sweet peas, notably a gene for purple (P)
vs. red (p) flowers, and a gene for long pollen grains (L)
vs. round pollen grains (l).

Answer 1

William Bateson and R.C. Punnett

Question 2

is a breeding or a mating between an individual of dominant phenotype, who could be either
homozygous dominant (SS) or heterozygous (Ss), with an
individual that MUST be homozygous recessive (ss)

Answer 2

test cross

Question 3

the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction.

Answer 3

genetic linkage

Question 4

Tendency of genes to remain together in their original
combination during inheritance is called

Answer 4

linkage

Question 5

is defined genetically as the failure of two genes to
assort independently.

Answer 5

linkage

Question 6

The trend of two or more genes to stay together in the same
chromosome during inheritance is referred to as

Answer 6

linkage

Question 7

a linkage in which crossing over does not occur. In other words, when only parental types are obtained from the test
cross progeny, it refers to absolute linkage

Answer 7

complete linkage

Question 8

a linkage in which crossing over occurs between linked genes. As a result along with parental combinations, recombination are also observed in the test cross progeny.

Answer 8

incomplete linkage

Question 9

It refers to linkage either between dominant genes or
between recessive genes. This type of linkage is found in pea, maize and several other crops.

Answer 9

coupling linkage

Question 10

It refers to linkage of some dominant genes with some
recessive genes. This type of linkage is found in pea, maize and several other crops.

Answer 10

repulsion linkage

Question 11

It refers to linkage of such genes which are located
on other sex chromosomes (Autosomes)

Answer 11

autosomal linkage

Question 12

It refers to linkage of such genes which are located on sex chromosomes

Answer 12

x-chromosomal linkage

Question 13

types of linkage

Answer 13

1. based on crossing over
2. based on genes involved
3. based on chromosomes involved

Question 14

The pairing starts at one or more points and proceeds along the
whole length in a zipper manner.

Answer 14

synapsis

Question 15

Four stranded stage of chromatids occurs
due to splitting of homologous chromosomes into sister chromatids
attached with un-splitted centromeres

Answer 15

duplication of chromosomes

Question 16

It occurs during pachytene stage. Non-sister chromatids of
homologous pair twist over each other due to action of enzyme
endonuclease.

Answer 16

crossing over

Question 17

mechanisms of crossing over

Answer 17

1. synapsis
2. duplication of chromosomes
3. crossing over

Question 18

is formed between two non-sister chromatids of homologous chromosomes

Answer 18

single CROSSING OVER

Question 19

In this condition, two chiasmata are formed between non-sister chromatids of homologous chromosomes

Answer 19

double-crossing over

Question 20

Presence of more than two crossovers between non-sister chromatids of homologous chromosomes.

Answer 20

multiple crossing over

Question 21

types of crossing over

Answer 21

1. single crossing over
2. double crossing over
3. multiple crossing over

Question 22

importance of crossing over:

Answer 22

1. creation of variability
2. locating genes
3. linkage maps

Question 23

is the process of determining the genes and
their location along the length of chromosome.

Answer 23

gene mapping

Question 24

The gene located on same chromosome inherits together
known as

Answer 24

linked gene

Question 25

is by counting the number of crossovers that occur
during meiosis.

Answer 25

gene map

Question 26

the distance between genes

Answer 26

map distance

Question 27

The unit of map distance is written as

Answer 27

centimorgan/map unit

Question 28

is done to determine the recombinant
frequency between 2 linked genes

Answer 28

two-point test cross