UNIT I Lecture..pdf

UNIT I Foundations of Animal Explain the theory of evolution Breeding: Evolution, Heredity and Domestication of Animals...

UNIT I Foundations of Animal Explain the theory of evolution Breeding: Evolution, Heredity and Domestication of Animals Identify historical contributions to the theories of heredity Describe the History of Animal Genetics and Livestock Domestication Topic Outline I. Evolution and Natural Selection II. Concepts of Heredity - Mendelian, Pre-Mendelian, Chromosome Theory III. Domestication of Animals IV. Development of Animal Breeding as a Science NATURAL EVOLUTION SELECTION the theory that all living things have changed in response to environmental Organisms that are more adapted to conditions by the natural selection of their environment are more likely randomly occurring mutations to survive and pass on the genes a complex process by which characteristics that aided their success of living organisms change over many generations as traits are passed from parents to offspring  EVOLUTION BY NATURAL 1. Giraffe (Giraffa spp.) SELECTION EXAMPLES - by Charles Darwin (1859) Giraffe English Peppered Moth Deer Mouse 2. English Peppered Moth (Biston betularia) 2. English Peppered Moth (Biston betularia) - by James William Tutt - by James William Tutt Light-colored Mutant dark-colored 3. Deer Mouse (Peromyscus spp.) History of the Theory of Evolution 611-547 BC Anaximander of Initiated the Theory of the Aquatic Descent of Man Miletus 493- 433 BC Empedocles humans and animals arose from antecedent monstrous forms 384-322 BC Aristotle Conceptualized the 1731- 1802 Erasmus Darwin Believed that all animals have a single origin 1744- 1829 Jean-Baptiste : 1. Use and disuse concept Lamarck 2. Transmission of acquired characteristics Forest-dwelling deer mouse Beach deer mouse sheltering Oldfield deer mouse found in perches high on a tree branch in among the dune grasses on the fallow fields 1766- 1834 Thomas Robert Southwestern Pennsylvania Florida's Atlantic coast Malthus introduced the concept of Proponent of the Theory of Evolution Through Natural Selection 1744- 1829 Charles Darwin  Lamarckian Evolution Concepts The Voyage of the Beagle 1. Use and disuse concept - Parts of the body that are used most to cope with the environment become larger and stronger over time, while those that are not used deteriorate 2. Transmission of acquired characteristics - Modifications that an organism acquires during its lifetime can be passed along to its offspring The Voyage of the Beagle Galapagos Finches Flora Fauna 5 Points of Alfred Russel Wallace (1823-1913) Variation -Organisms vary (they are not exactly alike their parents) Had come independently on the Inheritance -These variations may be hereditary theory of natural selection -Environmental resources are limited, so organisms Reached his conclusions roughly at Selection with advantageous characteristics make it easier for the same time as Darwin them to survive -As time passes, each generation continues to Time produce more offspring with advantageous characteristics. -Such traits eventually become more common in Adaptation the population, making the entire species better suited to survive in their environment. However - It lacked a satisfactory theory of heredity - Because of this, scientists continued to embrace Lamarckism Gregor Johann Heredity Mendel biological The Father of Modern Genetics through his work on pea plants (Pisum sativum) , discovered It is the sum of all biological the fundamental laws of processes by which inheritance. particular characteristics It took him eight years (1856- are transmitted from 1863) and 30,000 pea plants to parents to their offspring. discover the natural laws of heredity (now called Laws of Inheritance) Investigated the process of cell division and distribution of chromosomes to 1882 Walther Flemming the daughter nuclei; Coined the term 1. Every trait is controlled by heritable (now known as genes) 1887-1890 Theodor Boveri One of the first to see evidence of the process of meiosis 2. Each offspring inherits two factors, one from each parent 1900 Hugo Marie de Vries Carl Correns expand Erich von Tschermak awareness of the Mendelian laws of inheritance in the scientific world 3. If the two factors differ, one is dominant and one is recessive Hugo Marie de Published which 1901-1903 Vries gradual changes over long periods 4. The two factors for each character (one from each parent) separate 1902-1903 Walter Sutton Theodor Boveri proposed during gamete formation 1905 William Bateson Coined the name and other terms used in modern genetics - These generalizations were however ignored until the 1900s because Wilhelm Ludwig 1909 Proposed the term and coined the terms genotype and phenotype these were in opposition to the Darwinian concept of heredity Johannsen Thomas Hunt Experiments on the Fruit fly led him to the discovery of how genes are 1910 Morgan transmitted through the action of chromosomes Chromosomal Theory of Inheritance Proposed independently by He and his graduate Theodor Boveri and Walter students worked on the Sutton in 1902-1903 fruit fly (Drosophila States that genes are found at melanogaster) specific locations on chromosomes, and that the behavior of chromosomes during meiosis can explain Mendel's laws of inheritance The Modern Synthesis (1920-1950) How does it differ? A result of the integration of Darwinian evolution with 1. It recognizes several mechanisms of evolution in addition to natural selection (e.g. genetic drift) Diversity within a population arose from the random 2. It recognizes that characteristics are inherited as production of mutations, and the environment acted discrete entities called genes to select the most fit phenotypes. A theory about how evolution works at the level of 3. It postulates that speciation is (usually) due to the gradual accumulation of small genetic change genes, phenotypes, and populations Path to the Chromosomal Theory of Pangenesis Theory (1868) Inheritance Postulated by Hippocrates and Charles Darwin Suggests that all cells in an organism are capable of shedding minute particles he called gemmules 1. Mendelian Inheritance (1865) These gemmules circulate throughout the body and finally congregate in the gonads. 2. Pangenesis Theory (1868) These particles are then transmitted to the next generation 3. Germ-plasm Theory (1883)  Other Pre-Mendelian Theories of Germ-plasm Theory (1883) Heredity Proposed by August Weismann Asserted that germ plasm, which is independent from all other cells Moist Vapor Theory (Pythagoras) of the body (somatoplasm), is the essential element of germ cells (eggs and sperm) and is the hereditary material that is passed from Reproductive Blood Theory (Aristotle) generation to generation. Preformation Theory Blending Theory Moist Vapor Theory Reproductive Blood Theory by Greek philosopher Pythagoras by Aristotle (350BC) in 500 B.C. Menstrual fluid produced by women is the He believed that each organ in the impure female semen body of a male produced some kind of moist vapor Female semen and male semen combine During coitus, these vapors unite during mating to form the embryo which Female semen provides the inert substance develops in the female while the vital ingredient for embryo formation is provided by the male semen Preformation Theory Blending Theory Proposed by Swammerdam Jean-Baptiste Lamarck (1744 1829) (1679) and advocated by Fluid substance in the blood of Malpighi (1673) animals or in the sap of plants was believes that the organism is the hereditary material already present, i.e., preformed in the sperm or egg in a characteristics in the offspring was miniature form called believed to occur by a of. this fluid Fertilization is required to Result: traits in the offspring are stimulate its growth intermediate from those found in the parents Blending Theory Until 1900s, people believed this theory Unable to explain how genetic variation can persist over evolutionary time Domestication of Animals Domestication of Animals Domestication Before After taming an animal and keeping it as a pet Oxford Dictionary Nomadic lifestyle Sedentary lifestyle Hunting/Fishing Agriculture Can defined as the man's activity of taming the wild Livestock animals and to control the breeding, feeding and care Gathering (management and health control) Companionship Jay Lush (1945) Characteristics of Domestic Animals Adapt to the type of feed they are offered by humans. Survive and reproduce in the relatively closed quarters of captivity Naturally calm and only slightly disturbed by man or sudden change in environment They provide service or useful products with economic value. selectively bred and genetically adapted over generations to live alongside humans Tomar, S. (2004)  Domestic Cattle New Stone Age both in Europe and Asia Two types of domestic cattle: Origin of Domestic Animals Bos indicus (tropical) Bos taurus (temperate) Bos indicus Wild ancestor: Aurochs (Bos primigenius) Primarily used as draft animals and for milk production Assumed religious importance in many ancient civilizations Also served as a measure of how much wealth one possessed Bos taurus Domestic Cattle Domestic Sheep (Ovis aries) ca. 10,000 BC together with the New Stone Age both in Europe and Asia goat Two types of domestic cattle: Bos indicus (tropical) Remote ancestors of sheep: Bos taurus (temperate) - Mouflon (Ovis musimon) of Europe Mouflon (Ovis musimon) Wild ancestor: Aurochs (Bos primigenius) - Urial/Shapo (Ovis vignei) of Central and South Asia Primarily used as draft animals and for milk production Primarily raised for meat and milk Assumed religious importance in many Domesticated by people living in ancient civilizations Auroch (Bos primigenius) cold climates for their skin and Also served as a measure of how much selected for wool production wealth one possessed Urial (Ovis vignei) Domestic Goat (Capra aegagrus hircus) Domestic Pig (Sus scrofa domesticus) ca. 10,000 BC together with the 8500-8000 BC sheep Descended from two wild Ancestor of domestic goats: stocks -Bezoar ibex or Pasang (Capra Eurasian wild pigs (Sus scrofa) aegagrus aegagrus) of Iran and of Northern Europe Eurasian wild pig (Sus scrofa) adjacent regions Banded pigs (Sus vittatus) of Purpose of domestication: Indonesia - yield the underfur for Cashmere Purpose of domestication: shawls meat - provide mohair (soft silky wool of animal's skin or hide is used for the Angora goat) Bezoar ibex (Capra aegagrus leather - Milk and meat aegagrus) Banded pig (Sus vittatus) Domestic Chicken (Gallus gallus domesticus) 7,000-10,000 years ago in Southeast Asia and Oceana. Modern breeds descended from 4 subspecies: Red Junglefowl (Gallus gallus) Red Junglefowl (Gallus gallus) Ceylon Junglefowl (Gallus lafayetii) Ceylon Junglefowl (Gallus lafayetii) Gray Junglefowl (Gallus sonneratii) Green Junglefowl (Gallus varius) Purpose of domestication: it is believed that the sport of cockfighting was the principle reason ability to provide meat and eggs without being competitive for human food sources Grey Junglefowl (Gallus sonneratii) Green Junglefowl (Gallus varius) Horse (Equus caballus) Ancestors of the Modern Horse Probably the last animal to be domesticated around 6,000 years ago in Eurasia Purpose of domestication: mobility/transportation warfare draft animals in agriculture sport Ancestors of the Modern Horse Modern Horse Ancestors Eohippus/ Hyracotherium/ Eohippus/ Hyracotherium/ Dawn Horse Dawn Horse A small, fox-like animal with four A small, fox-like animal with four toes in front & three behind toes in front & three behind Mesohippus = middle horse Mesohippus = middle horse Has 3 toes lost metacarpal V Has 3 toes lost metacarpal V Merychippus Merychippus retained 3 toes retained 3 toes looked like a modern horse with its looked like a modern horse with its long face long face Pliohippus Pliohippus earliest one-toed horse earliest one-toed horse Modern Horse Ancestors Modern Horse Ancestors Eohippus/ Hyracotherium/ Eohippus/ Hyracotherium/ Dawn Horse Dawn Horse A small, fox-like animal with four A small, fox-like animal with four toes in front & 3 behind toes in front & 3 behind Mesohippus = middle horse Mesohippus = middle horse Has 3 toes lost metacarpal V Has 3 toes lost metacarpal V Merychippus Merychippus retained 3 toes retained 3 toes looked like a modern horse with its looked like a modern horse with its long face long face Pliohippus Pliohippus earliest one-toed horse earliest one-toed horse What is the last surviving species of Horse Hybrids wild horse? Mule - cross between a female horse Hinny - cross between a female (mare) and a male donkey (jack) donkey (jenny or jennet) and a male horse (stallion) Horse (Equus ferus przewalskii) Other domesticated animals Animal Breeding Animal Breeding History With domestication, Robert Bakewell (1725- selection of animals for Breeders practiced 1795) Father of Animal special purposes and Breeding -Britannica Encylopedia reproductive fitness began Charles Colling and The fields of Genetics and Robert Colling studied Early in the 20th century, Statistics joined to form -EFFAB breeding the works of Mendel were Population Genetics rediscovered and the procedures and (pioneered by Dr. Sewall foundations of genetics produced the Shorthorn Wright and Sir Ronald were organized breed Fisher) Important Aspects to Consider in Aims of Animal Breeding Animal Breeding 1. To select the most desirable animals based on the prediction of 1. The trait under selection is heritable. genetic merit 2. Animals have different genetic backgrounds so that selection is possible. 2. To produce superior genotypes by the combination of genetics 3. The direction of selection is defined by humans, and they through breeding plans and mating systems decide which animals are allowed to mate and produce members of the next generation. 3. To enhance efficiency of production and the quality of the 4. Success of animal breeding can be judged by looking at a shift product for the ultimate consumer through planned genetic in population. change 5. Success of animal breeding can be measured as the cumulative result of multiple generations of selection References Bourdon, R. (2014). Pearson New International Edition Tomar, S.S. (2004). Textbook of Animal Breeding. Kalyani Publishers. IND Klug, W.S., et. al. (2019). Concepts of genetics. 12th ed. Pearson Education, Inc. USA Zimmer, C. (2013).. The Loom- National Geographic. https://www.nationalgeographic.com/science/article/evol ution-in-color-from-peppered-moths-to-walking-sticks