Genetics
genetics
The scientific study of heredity
Gregor Mendel
Augustinian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)
trait
specific physical characteristic that varies from one individual to another
gene
section of DNA that codes for a specific trait
hybrid
a genotype with two different alleles.
allele
different forms of a gene
principle of dominance
Mendel’s second conclusion, which states that some alleles are dominant and others are recessive
gamete
specialized cell involved in sexual reproduction
fertilization
process in sexual reproduction in which male and female reproductive cells join to form a new cell
“true breeding”
term used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate
P generation
parental generation, the first two individuals that mate in a genetic cross
F1 generation
the first generation of offspring obtained from an experimental cross of two organisms
F2 generation
the second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation
probability
The likelihood that a particular event will occur
Punnett square
a chart that shows all the possible combinations of alleles that can result from a genetic cross
genotype
genetic makeup of an organism
phenotype
The physical traits that appear in an individual as a result of its gentic make up. What an organism looks like.
heterozygous
Scientific term for having two different alleles for a trait
homozygous
Scientific term for having two identical alleles for a trait
homozygous dominant
Scientific term for having two dominant alleles for a trait
homozygous recessive
Scientific term for having two recessive alleles for a trait
incomplete dominance
creates a blended phenotype; one allele is not completely dominant over the other
codominance
situation in which both alleles of a gene contribute to the phenotype of the organism
meiosis
(genetics) cell division that produces reproductive cells in sexually reproducing organisms
diploid
term used to refer to a cell that contains a complete set of chromosomes
haploid
an organism or cell having only a half set of chromosomes
homologous pair
pair of identical chromosomes
zygote
fertilized egg
pure
a genotype with two of the same alleles.
heredity
the study of genetics
For aliens the allele for a star antennae is dominant to the allele for no star. If a pure dominant alien is crosses with a hybrid alien, what would the genotypes of the offspring be?
SS and Ss
In aliens, Q=the allele for a smooth face and q= the allele for face spikes. Give the genotypes for the offspring from Qq x Qq
QQ, Qq, qq
In aliens, Q=the allele for a smooth face and q= the allele for face spikes. Give the phenotype ratio for the offspring.
3 smooth face: 1 face spikes
In a group of 12 people, 9 can roll their tongues and 3 cannot. Which phenotype is dominant?
tongue rolling
In a group of 12 people, 9 can roll their tongues and 3 cannot. What is the ratio?
3 tongue rolling:1 cannot roll tongue