genetics

Question 1

law of inheritance

Answer 1

offspring inherit their parent’s characteristics because they inherit their DNA
was shown by Mandell

Question 2

pedigrees show

Answer 2

the inheritance of a single phenotypic trait

Question 3

allele

Answer 3

• the various forms a particular gene can take
• is a section of DNA on a chromosome that codes for a particular protein

Question 4

carriers

Answer 4

they carry a recessive gene that can be passed on to their offspring but initially do not show the characteristic

Question 5

test cross

Answer 5

the mating of a pair where the genotype of one parent is homozygous recessive and we are trying to determine the genotype of the second parent

Question 6

hybrid

Answer 6

the offspring of a cross between two purebreds
- typically healthier than purebreds (hybrid vigour)

Question 7

independent assortment

Answer 7

• the inheritance of each characteristic is a separate event, they are not inherited together

Question 8

what is the exception to independent assortment

Answer 8

• when the genes are found on the same chromosome
• they are passed together
• are said to be linked

Question 9

incomplete dominance

Answer 9

the trait does not completely mask the recessive trait

eg. black fur with a few white hairs

Question 10

co-dominance

Answer 10

when both characteristics are present equally

half black and halpf white fur

Question 11

epistasis

Answer 11

• 2 different genes interact with and affect each other
• requires 2 genes

eg. coat color and blindness bbvv

Question 12

how many genes are on the y chromosome?

Answer 12

few

Question 13

how many genes are on the x chromosome

Answer 13

many

Question 14

sex-linked characteristics

Answer 14

characteristics that are determined by genes on the x chromosome

Question 15

sex-limited characteristics

Answer 15

characteristics expressed by only one sex

Question 16

how many chromosomes do dogs have

Answer 16

78

Question 17

how many chromosomes to cats have

Answer 17

38

Question 18

lethal genes

Answer 18

defective genes that are detrimental to the individual and are not compatible with life

Question 19

a gene is considered lethal if the individual dies before reaching what

Answer 19

reproductive maturity

Question 20

selective breeding

Answer 20

the owner wanting the best offspring and selecting the parents with that in mind

Question 21

artificial selection

Answer 21

selection of an animal mate based on the genotype of each animal

Question 22

natural selection

Answer 22

the animal chooses its own mate

Question 23

artificial selection rests on the principle of ________

Answer 23

variation

Question 24

variation

Answer 24

• the difference between individuals of the same species for any given characteristic
• the average difference between an individual’s performance and the mean average
• if there was no variation, mating pairs would not matter
• is represented on a bell curve

Question 25

2 major advantages of artificial selection

Answer 25

• aids in predicting the phenotype of the offspring
• may improve the quality of the breed by producing offspring that’s better than their parents

Question 26

mutations

Answer 26

• change in DNA structure
• maybe in every cell or just one