The document discusses non-Mendelian inheritance, focusing on concepts such as alleles, genotypes, phenotypes, and different inheritance patterns including incomplete dominance, codominance, and sex-linked traits. It highlights how traits can be expressed through various genetic combinations and provides examples such as blood types and phenotypic traits in animals. Additionally, it explains the concept of multiple alleles within a population.

1. Non-Mendelian Inheritance

2. Allele – alternative form of gene
- is one of two or more versions of DNA sequence (a single base
or a segment of bases) at a given genomic location.
Genotype - genetic makeup of an organism; in other words, it
describes an organism's complete set of genes.
Phenotype – observable traits of an organism (brown, tall, short)
Homozygous – gene combination having the same/identical alleles
for a single trait (HH)
Heterozygous – gene combination having two different alleles (Hh)

3. Dominant Traits - the traits which are expressed more often and
observed more commonly in the population is called dominant trait
Recessive Traits - can be carried in a person's genes without
appearing in that person. For example, a dark-haired person may
have one gene for dark hair, which is a dominant trait , and one gene
for light hair, which is recessive.

4. Non-Mendelian Inheritance
Incomplete Dominance
- is when the homozygous dominant trait is crossed with a recessive
trait, the result would be the expression of a trait that is in between
the dominant and recessive traits.
- in incomplete dominance, as the name implies, the offspring does
not completely express the dominant trait when the parent with the
homozygous dominant trait and parent with the recessive trait are
crossed.
- Ex. (R) Red Snapdragon + (r) White Snapdragon = Pink Snapdragon
100%pink

5. Codominance
- is when the two different traits are both present in an individual.
This means that a heterozygous genotype in codominance will
express both traits.
-Ex. (B)Black Chicken + (b)White Chicken = Checkered/Black and
White Colored Chicken(Bb)
-Ex. Blood type AB is codominance.

6. Sex-Linked Inheritance
- characteristics (or traits) that are influenced by genes carried on
the sex chromosomes. In humans, the term often refers to traits or
disorders influenced by genes on the X chromosome, as it contains
many more genes than the smaller Y chromosome.
-Color blindness is an example of an X-linked recessive trait. As the
name implies, X-linked traits are traits that are linked to the X
chromosome.
-There are 23 pairs of chromosomes or 46 chromosomes in humans.
-The first 22 pairs are termed as autosomes.
-The 23rd
pair is either XX or XY chromosomes.

7. Multiple Alleles
-a gene can have more than two allelic forms segregating within
a population. These genes are referred to as having multiple alleles.
-This does not mean that the gene in a particular individual possesses
more than two alleles. An individual can only have a maximum of two
of the alleles, one maternal and one paternal, no matter how many
alleles exist in the population.
-An example of multiple alleles is blood type. There are three alleles for
the ABO human blood type: A, B, and O.