Genotype and its types | class 10
Aslam o alikum
I am Hassam ur Rahman and I am teaching Fsc biology since 2014 .I am always trying to improve myself and provide best lecture to students.i am taking content for the lecture from authentic and relevant sources but human errors are possible . you are requested to please highlight the mistakes.My lectures are equally reliable for Fsc and mdcat students
#visiblescience #mdcatbiology #alevelbiology #neetbiology #fscbiology
My personal channel, I am sure it will change your life and very beneficial for you
/ @hassamurrahman
My Facebook page link
https://www.facebook.com/hassam.urahm...
This lecture is about
Genotype and its Types
The specific combination of genes in an individual is
known as genotype. It is of two types i.e. homozygous
and heterozygous. In order to understand the concept
of genotype, let us consider an example trait i.e.
albinism (a condition in which normal body pigments
are absent). Like other traits, it is also controlled by one
pair of genes. We can represent the two alleles of the
pair as ‘A’ and ‘a’. Three combinations i.e. genotypes
are possible for these two alleles i.e. AA, Aa, and aa.
These genotypes can be grouped into two types. The
genotype in which the gene pair contains two identical
alleles (AA or aa), is called homozygous genotype. The
genotype in which the gene pair contains two different
alleles (Aa), is called heterozygous genotype.
When in the heterozygous condition one allele masks
or prevents the expression of the other, it is called the dominant allele. The allele which is not
expressed is called recessive.
The dominant alleles are represented by capital letters and recessive alleles by lower case letters.
Albinism is a recessive trait i.e. it is produced when both alleles are recessive. In humans, allele ‘A’
produces normal body pigments while allele ‘a’ does not produce pigments. If genotype is AA or
Aa, the individual will produce pigments. On the other hand, if genotype is aa, no pigments will be
produced and the individual will be albino. In this example, you see that the allele ‘A’ dominates
over ‘a’, because in Aa indiviual pigments are produced and the effect of ‘a’ is suppressed by ‘A’.
The expression of this genotype in the form of trait (in our example, being albino or having normal
pigmentation) is known as the phenotype