Midterm 1

Question 1

What is a trait?

Answer 1

any observable characteristic of an individual

Question 2

what is a phenotype?

Answer 2

observed category of measured level of performance for a trait in an individual ex. red coat color

Question 3

genotype

Answer 3

genetic makeup of individual, constists of mom and dad contribution for everytrait

Question 4

crossbreeding

Answer 4

mating animals from different breeds

Question 5

heterosis

Answer 5

superiority of an outbred individual related to the average performance of populations (hybrid offpsring has imporved traits)

Question 6

inbreeding

Answer 6

mating of closely related individuals

Question 7

pure breeding

Answer 7

mating individual within the same breed- maintain bloodlines and pedigrees

Question 8

*dominance

Answer 8

heterozygote is identical to expression of homozygous genotype
- pheonotypically no difference
-prone to genetic disease

Question 9

*partial dominance

Answer 9

heterozygote is intermediate to expressions of homozygous genotypes, more closely resembles expression of homozygous dom. genotype

Question 10

*no dominance

Answer 10

heterozygote is exactly midway between expressions of homozygous genotypes

Question 11

enviornment effects

Answer 11

external effect factors (non-genetic) have on an animals performance

Question 12

relationship with each other

Answer 12

phenotype= genotype+enviornment

Question 13

homozygous

Answer 13

when both genes at a locus are functionally the same (AA or aa)

Question 14

heterozygous

Answer 14

when both genes are at a locus are functionally different (Aa)

Question 15

Gene

Answer 15

physical unit of heredity consisting of DNA sequence on chromosome

Question 16

DNA

Answer 16

heredity material in humans and all other organisms

Question 17

chromosome

Answer 17

long strand of DNA and associated proteins present in the nucleus of a cell

Question 18

locus

Answer 18

location of gene on chromosome

Question 19

allele

Answer 19

alternative form of gene, must be functionally different
-upper letter = most dom and listed first

Question 20

mitosis

Answer 20

creates exact copy of parent cells
- starts and ends w same # of chromosomes

Question 21

meosis

Answer 21

occurs in reproductive/germ cells (ovary and testies) leads to formation of Haploid cells

Question 22

mitosis vs meiosis

Answer 22

meiosis has 2 divisions (meiosis 1 and 2)

Question 23

prophase 1 (meiosis 1)

Answer 23

crossing over- physical exchange of chromosome pieces
- each daughter cell contains 1 pair of sister chromatids

Question 24

meiosis II

Answer 24

• no crossing over
  -4 haploid spermatids
  -genetically haploid

Question 25

mitosis

Answer 25

- 2 cells -both memebers of each pair of chromosomes -genetically diploid

Question 26

Rule #1 probability

Answer 26

probability of 2 independent events occuring together is the product of the probability of their individual occurences (RrxRr = 50% of "R" offspring)

Question 27

Rule #2 probability

Answer 27

Probability of one or the other of 2 mutually exclusive events occurring is = to the sum of the probabilities of their occurrences

Question 28

geno vs pheno ratios

Answer 28

G= 1:2:1 P= 3:1

Question 29

Dominance

Answer 29

Interaction between alleles and a single locus, allele with greater effect is dominant

Question 30

epistasis

Answer 30

interaction among gene at different loci, the allele present at one or more loci

Question 31

sex-linked

Answer 31

pattern of inheritance for genes located on sex chromosomes differs from mendelian pattern -lack corresponding regions of DNA

Question 32

sex limited inheritance

Answer 32

phenotypic expression is limited to 1 sex - milk production in female cows -hormonally conditioned -most are autosomal

Question 33

sex-influenced inheritance

Answer 33

modes of gene expression differ between males and females -allele may be dominant in male and rec. in female -can show up in both, but one more frequent in one sex

Question 34

law of segregation

Answer 34

seperation of paired gene during gamete formation=meiosis - gametes contain half the #of chromosomes and genes than normal body cells (somatic)

Question 35

law of independent assortment

Answer 35

Independent segregation of genes at different loci -all combos are possible -crossing over -ensures genetic variability -cant predict what combo of genes will be present= why siblings dont look alike

Question 36

marker assisted selection

Answer 36

selection for specific alleles using genetic markers -closely linked to loci of interest -visual phenotype

Question 37

gene transfer

Answer 37

transplantation of specific genes from one individual to another using lab techniques