inheritance

Question 1

phenotype

Answer 1

the outward, physical manifestation of an organism’s genetic code

Question 2

character

Answer 2

a heritable feature ( e.g flower colour )

Question 3

trait

Answer 3

a varient of each character ( e.g purple or white )

Question 4

genotype

Answer 4

the coded, inheritable information in an organisms DNA

Question 5

allele

Answer 5

a particular form of a gene, occupy the same locus (site/location) on the chromosome

Question 6

homozygous

Answer 6

alleles both the same

AA or aa

Question 7

heterozygous

Answer 7

two different alleles

Aa

Question 8

dominant allele

Answer 8

a variation of a gene that will produce a certain phenotype, even in the presence of other alleles

Question 9

recessive allele

Answer 9

type of allele which will not be manifested in an individual unless both of the individual’s copies of that gene have that particular genotype.

Question 10

mendel’s law of segregation

Answer 10

alleles segregate randomly into gametes: When gametes are formed, each allele of one parent segregates randomly into the gametes, such that half of the parent’s gametes carry each allele

Question 11

mendel’s law of independent assortment

Answer 11

each pair of alleles segregates independently of other pairs of alleles

Question 12

codominance

Answer 12

condition in which both alleles for one gene in a hetrozygous organism contribute to the phenotype

Question 13

incomplete dominance

Answer 13

form of gene interaction in which both alleles of a gene at a locus are being partially expressed

Question 14

lethal gene

Answer 14

a gene where particular allele combinations lead to the death of an individual; can be either dominant or recessive

Question 15

pleiotrophic genes

Answer 15

those that have more than one distinguishable effect

influences 2 or more phenotypic traits

Question 16

sex-linked genes

Answer 16

carried on the x chromosome

in mammals, males are the hetrogametic sex
Females : XX , Males : XY

Question 17

epistatic gene

Answer 17

gene that determines whether or not a trait will be expressed

( or called inhibiting genes )

Question 18

polygenetic traits

Answer 18

individual inheritable characters are often controlled by groups of several genes (‘polygenes’)

each allele intensifies or diminishes the phenotype

variation is continous or quantative

(also called quantitative inheritance

Question 19

genetic linkage

Answer 19

when alleles at seperate loci are inherited together and thus dont obey mendels law of segregation

Question 20

cytoplasmic inheritance

Answer 20

some traits are inherited from organellar DNA

Question 21

intragenomic conflict

Answer 21

where genes have phenotypic effects that promote their own transmission in detriment of the transmission of other genes that reside in the same genome.

Question 22

meiotic drive

Answer 22

any process which causes some genetic variants to be over-represented in the gametes which are formed during meiosis

Question 23

segregation distortion

Answer 23

the phenomenon in which genotypes deviate from expected Mendelian ratios in the progeny of a cross between two varieties or species

Question 24

B chromosomes

Answer 24

= ‘supernumeracy’ or ‘accessory chromosomes’

they are transmitted in germline cells more frequently than expected from Mendellian inheritance and can accumulate selfisly

found in all major groups of animals and plants