Assignment No 1:
Q1: What are the phenotypic and genotypic ratios in
Mendel Law of Independent assortment?
is the genetic makeup of an organism that include number of chromosomes, number
of genes, the sequence of genes or the inheritance pattern of an organism. They
are expressed in a pair of letters, usually which are alleles. The alleles pairs
genotype is commonly expressed as RR (each letter representing one allele) as a
dominant trait, Rr as co-dominant or as recessive. This example uses the letter
R, but difference letters are used to describe different traits. They are
actual fact just variables.
Phenotype is the physical appearance of an organism. Like the height of an
organism. The color of the skin or the color of eyes. The phenotype includes
physical characteristics behavior corres-ponding to such species, structures,
organs, behaviors reflexes etc.
Let’s BB or Bb is the coding for black hair. BB/Bb is the genotype and
the black hair is the phenotype.
According to Mendel Law of
Examples: Dihybrid cross, true breeding plants for two traits. For
example, a plant that had green pod color and yellow seed color was
cross-pollinated with a plant that had yellow pod color and green seeds.
The traits for green pod color (GG) and yellow seed color (YY) are
dominanat. Yellow pod color (gg) and green seed color (yy) are recessive. F1
plants heterozygous GgYy.
True breeding yellow All green
Green pods with x pods with green = with yellow seeds
Yellow seeds seeds
After observing the resuts of dihybrid cross, Mendel allowed all of the F1
plants to self pollinate.He reffered to these offspring as F2 generation.
Mendel noticed the 9:3:3:1 ratio.
Phenotypic ratio is 9:3:3:1.
Genotypic ratio is 1/16 (GGYY)
+2/16(Ggyy)+2/16(GgYy)+1/16(GGyy)+1/16(ggYY) + 4/16