Sex Linked Inheritance
Background: The relationship between genotype and phenotype in sex-
linked genes differs from that in autosomal genes. A female must have
two recessive alleles of a sex linked gene to express a recessive sex
linked trait. Just one recessive allele is needed for the same trait to be
expressed in a male. In this lab, you will model the inheritance pattern
of sex linked genes. www.tutorvista.com
Materials:
• 2 coins • Marker
• Masking tape • Index card with genetic cross
Procedures:
1. Use the tape and marker to label two coins with the genetic cross shown on your index card.
2. Determine which person will flip for “Mom” (representing the egg cell) and who will flip for
“Dad” (representing the sperm cell).
3. Continue to flip coins and record the genotype of the offspring until you have modeled 50 genetic
crosses. Make a data table to record each genetic cross that you model.
4. Calculate the genotype and phenotype probabilities for both males and females. Calculate the
frequency of male offspring and female offspring.
Sex
Genotype
Sex
Genotype
1
26
2
27
3
28
4
29
5
30
6
31
7
32
8
33
9
34
10
35
11
36
12
37
13
38
14
39
15
40
16
41
17
42
18
43
19
44
20
45
21
46
22
47
23
48
24
49
25
50
