1. • the study of heredity and variation. It aims to
understand how traits can be passed on to the
next generation
• Heredity - traits are passed on from parents to
offspring.
• Variation - demonstrates differences among
individuals.
2. • Austrian Monk who
discovered the basic
principles of heredity
through experiments in
his garden specifically
with pea plants.
• Father of Genetics
3. • Phenotype –observable or detectable
characteristics of an individual(ex. Tall,
short, color of the eyes)
• Genotype – genetic makeup of an
individual (ex.TT, Tt, tt)
• Homozygous – having same allele(AA,aa)
• Heterozygous – consisting of two different
allele(Aa)
4. • Alleles –alternate forms or varieties of a
gene
• Dominant Allele – allele that mask the
presence of recessive allele in the
phenotype
• Recessive Allele – allele that is masked in
the phenotype by the presence of
dominant allele. It is expressed when the
5. The Mendelian patterns of Inheritance were further explored by
modern geneticists for reason that there were other outcomes of
experimentations and inquiries that cannot answered by the Laws of
6. • One pattern discovered is that one allele is not
completely dominant over the other allele resulting
in the blending of characteristics or the
appearance of an intermediate phenotype
possessed by two parents.
• Example: Flower color of Hibiscus .
(gumamela) and Mirabilis jalapa (four o’clock
flower). The crossed between a red-colored flower
and another white-colored flower would result in the
production of offspring that are pink-colored.
11. • In some cases, the
heterozygous
characteristics are both
fully expressed in the F1
offspring.
• Example: coat color in
cattle, both red and white
coat colors in cattle are
13. 1.In horses, chestnut and white color are both
dominant. Horses heterozygous for this trait
are golden tan in color. Suppose a golden tan
horse is bred to a white –colored horse.
CC-chestnut color; WW-white color; CW-golden tan in
color
CW x WW
14. 2. In watermelons, dark green skin color in fruits is
dominant over light green skin color. When two
watermelons were crossed, their offspring all have skin
colors that are light green with stripes of dark green.
• What are the genotypes of the two parents? Of the
offspring formed?
? ?
? ? ?
? ? ?
Genotypes:
4:0 or 100% DL
Phenotype:
4:0 or 100% light green
with stripes of dark
green
15. 3. In cats, black and tan fur colors are both
dominant. When a cat with a black color is mated
to a cat with tan color, the offspring produced will
have a fur with tabby pattern. Suppose a
black(BB)cat mated with a tabby cat(BT).
B B
B ? ?
T ? ?
16.
17. • Traits are controlled by multiple
alleles.
• Example:
Human blood groups – A, B, AB and O.
Coat color in Rabbits-Agouti, Chinchilla,
Himalayan and Albino.
In genetics, “dominant” genes are those that are always expressed if they are found in an organism. Dominant genes may be expressed as co-dominant (where two different traits are both expressed alongside each other) or as dominant/recessive (where the presence of a dominant gene completely masks the presence of a recessive gene).
Livestock
When a chicken with white feathers breeds with a chicken with black feathers, the result is an offspring that grows up to have both black and white feathers. Likewise, when a red cattle breeds with a white cattle, the resulting offspring may show both red and white hairs resulting in a mixed coat pattern called “roan.”
Rhododendron
Rhododendrons and other flowers may also exhibit codominance. In the case of rhododendrons, the crossing of a red and white flower may yield a flower that has both red and white patches. Many flowers show similar patterns of codominance, where both of the parental flower colors show up in different parts of the plant.
