Question

In the near future a Space X mission to Mars discovered a species that was previously unknown. Elon Musk decided to name the species "Gazorp". The size of this species was determined by a single gene. Individuals in this species could be either TT- Tall Tt- Medium and tt- Short. When the Gazorp reproduces, it produces 100 individuals. The scientists took the species back to earth and crossed two medium Gazorps in a lab. Out of the one hundred Gazorps produces how many would you expect to be medium sized?

Answer 1

Answer:

• 25 tall individuals, TT
• 50 medium individuals, Tt
• 25 short individuals, tt

Explanation:

Available data:

• The size of this species was determined by a single gene
• TT- Tall
• Tt- Medium
• tt- Short
• Total number of individuals in the progeny, N = 100

There are three phenotypes and only one gene, so it seems that this is an example of incomplete dominance, where the medium-size is the intermediate form between tall-size and short-size.  

Cross: between two medium Gazorps

Parentals) Tt    x    Tt

Gametes) T  t       T   t

Punnett square)    T           t

                    T       TT         Tt

                    t        tT          tt

F1) 1/4 = 25% TT, tall

    2/4 = 1/2 = 50% Tt, medium

    1/4 = 25% tt, short

100% of the progeny ------------ 100 individuals

25% Tall, TT ------------------------X = 25 individuals

50% Medium, Tt -------------------X = 50 individuals

25% Short, tt ------------------------X = 25 individuals