Biology
Name:
Karyotype activity
1. Get a male or a female normal karyotype image.
2. Determine your phenotype (what the trait looks like) for each of the traits listed in Table 1.
To help with this process, refer to the pictures for these phenotypes on the powerpoint.
3. Determine your genotype that produced your phenotype. (Note: For a dominant phenotype,
the genotype could be heterozygous (Rr) or homozygous (RR).) For this activity, flip a coin or
roll a dice to determine which of the two genotypes you should use.
4. Next, locate each gene pair on the appropriate chromosome (see Table 1) in your human
karyotype. For example, if you are heterozygous (Rr) for the trait on chromosome pair 22, you
should label one of the chromosomes with "R" and the other chromosome with "r." Since these
chromosomes have gone through duplication in preparation for division, they will each have
two identical letters (allele) for that gene.
5.It is estimated that we all carry between six and nine lethal recessive genes. For this exercise,
assume you are all carrying (heterozygous) the recessive disorders in Table 2. Assign their
genes to the appropriate chromosome like you did earlier.
TABLE 1
Trait
color of iris
Chromosome for
Gene Location
2
Dominant
Phenotype
Possible
Dominant
Genotypes
Recessive
Phenotype
Recessive
Genotype
not blue
EE or Ee
blue
ee
widow's peak 4
peak
PP or Pp
no peak
pp
cheek dimples 5
dimples
DD or Dd
not dimples
dd
face freckles
9
freckles
FF or Ff
no freckles
ff
mid-digital
hair
10
hair
HH or Hh
no hair
hh
Hitchhiker's
thumb
17
straight
TT or Tt
curved
tt
Hallux length
20
(toes)
long 2nd toe
BB or Bb
long big toe or
bb
= to 2nd toe
ear lobes
free
LL or Ll
attached
ll
tongue rolling 22
ability
RR or Rr
no ability
rr
cleft chin
cleft
YY or Yy
no cleft
yy
21
16
TABLE 2
Trait
Chromosome for Gene Location
Genotype
skin cancer
1
Cc
cystic fibrosis
7
Qq
albinism
11
Aa
xeroderma pigmentosa 15
Xx
lung cancer
Nn
3
PKU (phenylketonuria) 12
Gg
Muscular Dystrophy
Mm (girls only)
X sex chromosome
6. Attach your finished karyotype to this paper and turn in.