PPT 17 Genetics

Question 1

T or F. More has been accomplished by the application of genetics to poultry than any other livestock.

Answer 1

True

Question 2

what are the 3 objectives that commercial breeders are trying to accomplish?

Answer 2

1. increase output per bird
2. increase efficiency of production
3. improved quality of the product and disease resistance.

Question 3

what is a chromosome?

Answer 3

Cel that contains DNA and associated proteins in its nucleus that carry genetic information.

Question 4

how many pair of chromosomes do chickens have?

Answer 4

39, 38 are autosome pair and 1 sex chromosome.

Question 5

what is a gene?

Answer 5

unit of heredity DNA sequence that codes for specific protein products(thousands per chromosomes)

Question 6

what is a locus?

Answer 6

location on a chromosome where a specific gene resides.

Question 7

what is an allele?

Answer 7

it is the genetic form of a trait at a specific locus.

Question 8

what is a somatic cell? what do they contain?

Answer 8

all cells in the body except sex cells.

contains full complement of DNA.

Question 9

what are sex cells? What do they contain?

Answer 9

sperm or egg cells

1/2 complement of DNA

Question 10

how many pairs of large chromosomes do chickens have?

Answer 10

5 or 6

Question 11

what are qualitative traits? give examples.

Answer 11

simplest of inheritance. single gene trait determines comb type, feather color, etc.

Question 12

what are quantitative traits? give examples.

Answer 12

multiple genes interact to determine traits. body weight, # of eggs layer, etc.

Question 13

T or F. Environment can effect gene traits.

Answer 13

True

Question 14

what cell replication to somatic cells undergo? sex cells?

Answer 14

mitosis(full complement)

meiosis(1/2 complement)

Question 15

define dominance.

Answer 15

ability of one gene to mask the expression of its allele.

Question 16

define recessive.

Answer 16

an allele that is not expressed

Question 17

define incomplete dominance.

Answer 17

the production of an intermediate phenotype in heterozygotes.

Question 18

Phenotypic expression means what?

Answer 18

traits that are visible

Question 19

genotypic expressions mean what?

Answer 19

allelic makeup responsible for traits

Question 20

male sex genes are _______?

Answer 20

homogametiic (ZZ)

Question 21

female sex genes are ______?

Answer 21

heterogametic (ZW)

Question 22

phenotypes of sex linked genes are only associated with what gene?

Answer 22

Z gene

Question 23

if we want to increase breast meat yield genetic heredity will yield a bird with decreased _________?

Answer 23

hatchability, egg #’s, and disease resistance

Question 24

If we want to increase growth rate the quantitative results cause what?

Answer 24

increased fatness and leg problems, but decreases livability and hatchability

Question 25

what type of breeding is used to result in pedigree lines?

Answer 25

inbreeding

Question 26

cross breeding is also known as what?

Answer 26

heterosis

Question 27

what is meant by “Hybrid Vigor”?

Answer 27

mating of different inbred populations

Question 28

what does a hybrid vigor result in?

Answer 28

a progeny that perform better than either parent.