Intro to Genetics Vocabulary
Know the following vocabulary words:
Heredity: the passing of __traits__ from ___parent__ to ___offspring___
Genes: Segments of DNA that carry __hereditary __ ___instructions__ and are passed to
offspring. Located on __chromosomes___.
Alleles: Different forms of the same __gene__
Dominant trait: The trait observed when at least __one_ ___dominant__ ___allele_ for a
characteristic is ___inherited__. Represented by a __capitol_ ___letter__.
Recessive trait: The trait that is apparent only when __two_ __recessive__ __alleles__ for
the same characteristic is __inherited___.
Represented by a _lower-case_ __letter__.
Genotype: The _genetic___ _make-up_ of an organism (in letters). The inherited
combination of __alleles__
Phenotype: An organisms inherited ___physical__ __appearance__.
Homozygous: When an organism has two alleles that are the _same__
Ex: TT ; GG
;
dd
Heterozygous: When an organism has two alleles that are __different__
Ex: Tt ; Gg
PRACTICE:
; Dd
identify if the following genotypes are homozygous (HO) or Heterozygous (HE)
1) TT ______________
2) yy ______________
3) Xx ______________
4) Gg ______________
5) Rr ______________
6) WW ______________
PRACTICE:
What phenotype would show?
T – tall
t- short
B- brown eyes
b- Blue eyes
7) TT ______________
8) Tt ______________
9) tt ______________
10) BB ______________
11) Bb ______________
12) bb ______________
Practice Writing Genotypes
Use the following to write the correct genotypes for the description below
Pea Plants
Guinea Pig
(Height)
T- tall
t- short
(position)
A- axial
a- terminal
(flower color) R- red
r- white
(Pod color)
g- yellow pod
G- green pod
(hair color)
(Hair length)
(hair texture)
B- black
b- white
L- short hair
l- long hair
S- smooth
s- rough
______________1. Pea plant homozygous recessive for height and heterozygous for flower
color.
______________2. Pea plant heterozygous for flower position and homozygous dominant for
color.
______________3. Pea plant heterozygous for height and homozygous recessive for flower
color.
______________4. Pea plant homozygous dominant for flower position and heterozygous for
pod color.
______________5. Pea plant homozygous dominant for height and heterozygous for flower
color.
______________6. Guinea pig homozygous recessive for color and homozygous dominant for
hair length.
______________7. Guinea pig heterozygous for color and homozygous recessive for hair
length.
______________8. Guinea pig homozygous recessive for color and hair length.
______________9. Guinea pig homozygous dominant for color and heterozygous for hair
texture.