The most common type of haemophilia results from the congenital absence of 

Definitions / Explanation : Epistatic Gene or Inhibitory Gene
 

In pea plants, red flowers $(R)$ are dominant over to white flowers $(r)$ and tall plants $(T)$ are dominant over to dwarf plants $(t)$. The table below shows the gametes and the possible offsprings produced in a dihybrid cross. The numbers $1$ to $16$ represent the genotypes of each individual cross $(e.g. 3 = RrTT)$

                $RT$      $Rt$     $rT$      $rt$

$RT$             $1$        $2$       $3$       $4$

$Rt$              $5$        $6$       $7$       $8$

$rT$              $9$        $10$     $11$     $12$

$rt$               $13$       $14$     $15$    $16$

If plant $7$ is crossed with plant $12$, then what proportion of the offsprings produced will be homozygous for both the recessive characters

$21$ trisomy in humans causes

The phenomenon in which an allele of one gene suppresses the activity of an allele of another gene is known as

The term "genotype'' was coined by