Question

in people sickle cell disease is expressed codominantly. when an individual is heterozygous they have both normal and sickled cells, but has only sickled cells when they have only recessive alleles. what is the phenotypic ratio of offspring with two heterozygous parents?

Answer 1

The phenotypic ratio of offspring with two sickle cell heterozygous parents is normal cells: sickle cell = 3 : 1.

Sickle cell is a genetic condition that causes the red blood cells to become abnormal. Sickle cell is caused by a gene mutation that is passed down from both parents, and both parents must have this genetic disorder.

Normal and sickle cell heterozygous genotype =  $Hb^AHb^S$  

Normal cell homozygous genotype = $Hb^AHb^A$  

Sickle cell homozygous genotype =  $Hb^SHb^S$  

If both parents are heterozygous then the cross is:

Parents: $Hb^AHb^S$   x  $Hb^AHb^S$  

Gametes:  $Hb^A,Hb^S$    x    $Hb^A,Hb^S$

F1 Generation:

$Hb^AHb^A$ (normal cells)

$Hb^AHb^S$ (normal and sickle cell)

$Hb^AHb^S$  (normal and sickle cell)

$Hb^SHb^S$ (sickle cell)

The genotype ratio of the offspring is  $Hb^AHb^A$ : $Hb^AHb^S$:  $Hb^SHb^S$ = 1 : 2 : 1

The phenotypic ratio of the offspring is Normal cells : Sickle cells = 3 : 1

Learn more about sickle cell heterozygote at https://brainly.com/question/13421900

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