Lecture 1. Genetics: Science of Heredity and Variation

principles governing heredity across generations

what is explained in genetics? (3)

the forces behind the diversities

what is explained in genetics? (2)

"grow into something", "to become"

came from the greek word "gen" which means

genes

determines the structure, function, and other biological properties of the character or trait

Blending Process

parent one + parent two = offspring

theory of germplasm

august weismann (1834-1914)

electron micrograph of nucleic acids

What is the molecule depicted in the powepoint?

carbohydrates, lipids, proteins, nucleic acids

What are the biomolecules?

Genetics

it is a branch of biology that deals heredity and variation in all living things

- molecular diversity at both molecular and physical levels

what is explained in genetics? (1)

Genetics

addresses life's fundamental questions

heredity

inheritance of traits from parents to offsprings between succeeding generations

you can select (if there is variation, there is evolution)

why is variation important?

(endemic) where do coconuts get their names from?

from the place they came from

baybay tall, albuera dwarf

what are some variations of coconut trees nearby?

macapuno (mutant)

high value, mahal, full of coconut meat

Genetics

it is multi-faceted

Genetics

stimulated by independent and related studies

William Bateson

coined the word "genetics"

1906

when was the word "genetics" coined?

Gregor Mendel in 1866

said that unit factors are transmitted in a uniform, predictable fashion

Gregor Mendel in 1866

- each progeny has a physical copy of the gene

genes

what are unit factors now called?

Blending Process

account for the children's intermediate nature

in between

what does "intermediate" mean?

theory of pangenesis

aristotle's theory (384-322 BC)

semen

-formed everywhere in a man's body

semen

reflected the characteristics of the body part from where it is formed

semen

traveled through the blood vessels into the male reproductive organs

theory of inheritance of acquired characteristics

jean baptiste de lamarck's theory (1744-1829)

jean baptiste de lamarck

proposed the fundamental mechanism of evolutionary change

theory of inheritance of acquired characteristics

body modification acquired by use or disuse could be transmitted to the offsprings because semen formed reflected such modifications

august weismann

conducted experiments about the inheritance of mice tails

normal tail lengths

cutting off of tails produced offsprings with

germplasm which was unaffected when tail was cut

inheritance did not depend on the particles in the parental tail but

Kolreuter (1733-1806)

hybrids between species have uniform appearance while fertile offsprings produce considerable diversity

Gartner

Naudin

Darwin

had the same conclusion as Kolreuter

Dzierzon

- a bee-hybridizer

- he said none of them took into account the numerical ratios

the choice of gardnen peas (pisum sativum) as the experimental material

- self-pollinated, relatively homozygous

- produced large number of seeds so characteristic ratio could be recognized easily

why was mendel considered the father of modern genetics? (1)

he concentrated on a single character at a time

why was mendel considered the father of modern genetics? (2)

strains or varieties were true-breeding by growing them for two years

why was mendel considered the father of modern genetics? (3)

flower color (purple and white), flower position (axial and terminal), seed color (yellow and green), seed shape (round and wrinkled), pod shape (inflated and constricted), pod color (green and yellow), stem length (tall and dwarf)

what are examples of characters (traits)?

he classified hybrid progenies and determined their respective frequencies

why was mendel considered the father of modern genetics? (4)

he formulated theories that explained his experimental results

why was mendel considered the father of modern genetics? (5)

he formulated experimental tests that validates his theories

why was mendel considered the father of modern genetics? (6)

40 years

mendel's work in 1866 was almost not considered important for how many years?

most biologists and mathematicians pay little appreciation to each other

the following are the reasons: (1)

he failed to prove his principles in other plants and animals

the following are the reasons: (2)

Carl Correns

Erich Von Tschermak

Hugo de Vries

they independently duplicated mendel's experiments in 1900

William Bateson

Saunders

Cuenot

they showed that mendel's principles also applied to animals in 1902

walter sutton (usa) and theodor boveri (germany)

independently suggested resemblance between mendelian factors and chromosomes

walter sutton (usa) and theodor boveri (germany)

segregation of pairs of factors and homologous chromosomes parallel each other during meiosis

thomas hunt morgan and calvin bridges

discovered sex chromosomes

thomas hunt morgan and calvin bridges

demonstrated the association between specific genes and chromosomes

thomas hunt morgan and calvin bridges

- according to them, each chromosomes contained not one but many genes

oswald avery, collin macLeod, maclyn macCarty

identified the deoxyribonucleic acid as the genetic material in 1944

james watson and francis crick

proposed the model of the dna in 1953

double helix model of the dna

explain how genes or dna are transmitted and expressed from generation to generation

oswald avery

bacteriophage

-individual

-species

-living forms as a whole

-similarities and differences encountered in the human species and degree of plasticity

what are the scope of genetics

individual

unique, inherent pattern in dynamic interplay with the environment are the central problems of life

species

ability to transfer these systems to the other generations

living forms as a whole

orderly variety of patterns and their changes with time on a geological scale constitute the accomplishment of organic evolution

similarities and differences encountered in the human species and degree of plasticity

are basic to human understanding and important to human welfare

- plant, animal, and microbial improvement

- medicine

- genetic counselling

- legal applications

- recombinant dna technology

what are the applications of genetics?

Plant, animal, and

microbial improvement

By selective breeding resulted in a litany of

success stories

❑ High-yielding and pest-resistant varieties of

rice, corn, and wheat

❑ Advances in meat production of cattle,

swine, and poultry through breeding

❑ Microbial strains selected for higher

efficiency in fermentation

medicine

Identification of diseases and

abnormalities which have genetic bases

and prescription of appropriate

preventive measures

genetic counseling

Knowledge of the inheritance of certain

desirable or undesirable characteristics,

as well as pedigrees of prospective

parents

legal applications

Helped solve problems of disputed

parentage in settling child support,

estate claims, or even baby mix-up in

hospitals

recombinant dna technology

Involves joining of DNA segments from

different biological sources producing

genetically modified organisms or

transgenic plants, animals, or

microorganisms

recombinant dna technology

❑ Therapeutic proteins, hormones, and

vaccines are produced using this

technique

legal applications

❑ Traits commonly used are DNA

"fingerprints" or profiles, ABO and MN

blood types, some enzyme markers

medicine

❑ Nature of these defects is known,

making it easy to take the necessary

preventive steps including gene therapy

Non-mendelian sex-linked trait

refers to characteristics (or traits) that are influenced by genes carried on the sex chromosomes.