genetic terminology

Question 1

gene

Answer 1

short section of a chromosome that codes for a particular characteristic

Question 2

allele

Answer 2

a particular form of gene

Question 3

phenotype

Answer 3

the outward appearance of an individual in terms of the trait under consideration

Question 4

genotype

Answer 4

the two alleles of a particular characteristic

Question 5

homozygous

Answer 5

both alleles of the gene are the same

Question 6

pure breeding

Answer 6

breeding with homozygous dominant or homozygous recessive

Question 7

heterozygous

Answer 7

the alleles of the gene are different

Question 8

dominant

Answer 8

in the heterozygous condition the dominant alleles will override the recessive alleles

Question 9

recessive

Answer 9

the recessive alleles will be dominated by the dominant allele - it only shows itself in the phenotype if there are 2 recessive alleles (tt)

Question 10

mendels first law of inheritance(law of segregation)

Answer 10

the two alleles of each gene separate during meiosis with only one entering each gamete

Question 11

gene locus

Answer 11

the position of the gene on the chromosome

Question 12

mono hybrid inheritance

Answer 12

the inheritance of a characteristic controlled by a single gene

Question 13

test cross

Answer 13

to determine the unknown genotype of an individual with a dominant phenotype, cross the unknown individual with a HOMOZYGOUS RECESSIVE. the ratio of phenotypes will determine the unknown genotype

Question 14

codominance

Answer 14

the two alleles at a gene locus are different but neither are dominant or can mask the other

Question 15

multiple alleles

Answer 15

the two alleles for a particular gene in a population at the gene locus eg.blood groups

Question 16

partial dominance

Answer 16

when both alleles are expressed often resulting in an intermediate or different phenotype

Question 17

lethal alleles

Answer 17

certain allele combinations result in a genotype that is not viable ie will not survive

Question 18

autosomes

Answer 18

22 pairs of chromosomes which are not sex chromosomes

Question 19

sex determination

Answer 19

sex chromosomes XX or XY determine sex of an individual

Question 20

pedigree charts

Answer 20

a diagram to chart the inheritance of a condition or trait through several generations or breeding groupsm

Question 21

dihybrid inheritance

Answer 21

when two characteristics are studied and is determined my two different genes on chromosomes from seperate homologous pairs
the genes that are on different chromosomes are said to be independent inherited