BIOL1040 Lecture 18: GENETICS 1 & 2
GENETICS 1 & 2
LEARNING GOALS
• Basis of heritability
• Mendelian genetics
• Ratios of inheritance
• Dominant vs recessive
• Pleiotrop, epistasis, polgenic inheritance • Se linked disease
• Gene disorders
HEREDITY
Refers to the genetic makeup of an individual based on genetic characteristics passed on from their
parents.
MENDEL AND THE GARDEN PEA
Gregor Mendel worked out the rules of inheritance in 1865, through experiments with garden peas.
In the early 20th century Sutton and Boveri formulated the chromosome theory of inheritance.
He had 2 hypothesis' that had been formulated to try and answer this question.
• Blending inheritance, parental traits blend such that their offspring have intermediate traits.
• Inheritance of acquired characteristics, potential traits are modified then passed onto their
offspring.
The pea was used for many reasons: easy to grow, short reproductive cycle, produces large number
of seeds, mating's are easy to control and traits are easily recognisable.
WHAT TRAITS DID HE STUDY?
Seed shape, seed colour, pad shape, pod colour, flower colour and pod position and stem length.
MENDELS EXPERIMEMTS
The blending model would mean the flowers should have been light purple.
His conclusion from this experiment was that the white flower trait was hidden in the first
generation.
MENDELS LAWS IN GENETICS
Law of segregation - each gene pair segregate or separate into different gamete cells during the
formation of the eggs and sperm in their parents. Each gamete gets only one from the pair.
The law of independent assortment - states that alleles of different genes are transmitted to egg
cells and the sperm cells independent of each other.
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Document Summary
Learning goals: basis of heritability, mendelian genetics, ratios of inheritance, dominant vs recessive, pleiotrop(cid:455), epistasis, pol(cid:455)genic inheritance se(cid:454) linked disease, gene disorders. Refers to the genetic makeup of an individual based on genetic characteristics passed on from their parents. Gregor mendel worked out the rules of inheritance in 1865, through experiments with garden peas. In the early 20th century sutton and boveri formulated the chromosome theory of inheritance. He had 2 hypothesis" that had been formulated to try and answer this question: blending inheritance, parental traits blend such that their offspring have intermediate traits. Inheritance of acquired characteristics, potential traits are modified then passed onto their offspring. The pea was used for many reasons: easy to grow, short reproductive cycle, produces large number of seeds, mating"s are easy to control and traits are easily recognisable. Seed shape, seed colour, pad shape, pod colour, flower colour and pod position and stem length.