Download yy - Denton ISD

VOCABULARY
GENETICS
Traits – inherited
characteristics
ex. Brown eyes, black hair…
Allele – different forms of a
gene for each variation of a
trait
ex. Y or y
Dominant – allele that is always
expressed if it is present
ex. YY - yellow Yy - yellow
YY or Yy
Recessive – allele that is only
expressed if dominant allele is
not present
ex. yy - green
yy
Homozygous –two alleles
for a trait are the same
or
yy
yy
Heterozygous – two alleles
for a trait are different
Yy
Genotype – allele
combination that forms
the gene
yy or yy or Yy
Phenotype – Physical
characteristics of an
organism
or
Gene – segment of DNA that
codes for a trait
Examples of genotype and phenotype
Example:
The genotype for mice fur color is: BB
The phenotype is brown fur
BB = Homozygous dominant
Example:
The genotype for hair type is: Hh
The phenotype is short hair
Hh = heterozygous
BB
Bb bb
Example:
The genotype for peas are: bb
The phenotype is wrinkled
bb = Homozygous recessive
Example:
The genotype for fly eye color is: Gg
The phenotype is green eyes
Gg = Heterozygous
RR
Rr
rr
Example:
The genotype for flower color is: Rr
The phenotype is pink
Rr = Heterozygous
Heterozygous
= different alleles
Aa
Homozygous
= same alleles
AA
aa
Heterozygous
Aa
Homozygous dominant
AA
Homozygous recessive
aa