genetics terms

Question 1

gene

Answer 1

a sequence of nucleotides on a nucleic acid molecule (DNA or RNA) that codes for a polypeptide(or RNA)

Question 2

locus

Answer 2

location of a gene on the chromosome

Question 3

homologous chromosomes

Answer 3

chromosomes from each parent that have the same length, shape, position of centromere, and alleles of genes in the same order

Question 4

character

Answer 4

a heritable feature that varies among individuals

Question 5

trait

Answer 5

each variant for a character

Question 6

alleles

Answer 6

different forms of a gene, have slightly different nucleotide sequence

Question 7

dominant alleles

Answer 7

effect seen in F1 phenotype, indicated by capital letters

Question 8

recessive alleles

Answer 8

effect not seen in F1 phenotype, indicated by lower case letters

Question 9

homozygous

Answer 9

cells or individuals with two copies of the same allele

Question 10

heterozygous

Answer 10

cells or individuals with two different alleles

Question 11

genotype

Answer 11

genetic make-up of an individual

Question 12

phenotype

Answer 12

appearance or expression of an allele combination

Question 13

wild type

Answer 13

the most common phenotype or allele for a gene in a population

Question 14

incomplete dominance

Answer 14

heterozygote shows effect of both allele

Question 15

codominance

Answer 15

both alleles are equally expressed

Question 16

I^A

Answer 16

antigen A (carbohydrate A)

Question 17

I^B

Answer 17

antigen B (carbohydrate B)

Question 18

i

Answer 18

no antigen

Question 19

multiple alleles

Answer 19

more than two alleles for a been in a population

Question 20

pleiotropic allele

Answer 20

allele has more than one effect, most alleles

Question 21

epistasis

Answer 21

interacting genes do not have equal effects, been at one locus alters the phenotypic expression of a gene at a different locus

Question 22

polygenic inheritance

Answer 22

add two or more genes

Question 23

quantitative characters

Answer 23

characters that vary in a population along a continuum, usually polygenic

Question 24

polygenic inheritance

Answer 24

additive effect of two or more genes determines phenotype
-phenotype often varies along a range, genes often interact with the environment as the number of genes increase, the number of phenotypic classes increase

Question 25

norm of reaction

Answer 25

range of phenotypes depending upon environment (phenotypic plasticity)

Question 26

multifactorial characters

Answer 26

many factors both genetic and environmental influence phenotype

Question 27

consanguinity

Answer 27

members of the same family mate

Question 28

carrier

Answer 28

heterozygotes who carry the recessive allele, usually normal phenotype

Question 29

X-linked traits

Answer 29

determined bygenes located on X chromosomes female has two alleles male has one allele for each trait (hemizygous)

Question 30

Y-linked traits

Answer 30

determined by genes located on the Y chromosome | many associated with maleness

Question 31

SRY gene

Answer 31

sex determining gene on Y chromosomal needed for testicle development