BASIC GENETIC TERMSII Asist Prof Nket BLGEN A

BASIC GENETIC TERMS-II Asist. Prof. Nüket BİLGEN A. U. Vet. Med. Department of Genetics

https: //www. nature. com/scitable/ https: //sciencemag. org/ https: //www. nature. com/ https: //www. the-scientist. com/tag/veterinary-medicine, genetics-genomics

Cloning animals Genetic bacground of diseases Gene therapy in treatment of diseases, Solving criminal cases with genetic information’s help

Introduction to genetics Definition of genetics and development genetics as a science Genetics is the study of inheritance. Genetic analysis how certain characters transmitted through generations.

The Simpsons Marge Homer Bart Lisa Maggie

Hair color, Posture, Eyes Weight, Hair stayle https: //www. slideshare. net/Maria__Carmen/simpsons-inheritance-powerpoint 11214738

What about the kids?

Homework Pedigree Prepare your family pedigree with photos. How many years you can go back? Can you find any similarites between you and your relatives?

Did you ever eat DNA?

Prehistoric Genetics We have good empirical evidence that humans had an implicit knowledge of genetics from at least 15, 000 years BCE. The evidence resides in the remnants of the first attempts at “genetic engineering. ” Nowadays we call it “artificial selection”—deliberately breeding of plants and animals for desired characteristics. The best empirical evidence comes from the analysis of pollen in hermetically sealed ancient tombs and from the dog.

Early Historical Period First hypothesis Beside Geometry Pythagorean (500 BC) was also proposed hypothesis on inheritance. Later his proposals were improved by Empedocles. However they were not even close being true.

Early Historical Period First hypothesis Hippocrates developed the first known theory of inheritance in Greece in the fifth century BCE. This could be classified as “bricks and mortar” theory. The hereditary material consists of physical material. He postulated that elements from all parts of the body became concentrated in male semen and then formed into a human in the womb. He also believed in the inheritance of acquired characteristic. Meaning the large biceps of an Olympic weightlifter result in many “bicep parts” accumulating in the semen. Hence, his children would also have big biceps.

First hypothesis of inheritance Aristotle criticized Hippocrates’ theory with 2 questions. 1. How mutilated and physically handicapped people can have normal children? If a guy lost his right leg, he would no longer have right leg body part. Hence his offspring would not have right leg.

First hypothesis of inheritance 2. People can transmit characteristics that they do not show at conception but develop at a later age. • Think of gray hair or male pattern baldness. • At the time of conception, most Greeks of the period would have brown to black hair and only a few would exhibit pattern baldness. • Hence, there are no “gray hair parts” and few “baldness parts” although much later in life those “body parts” might be available. Still parents can transmit these traits to their offspring. Than what was his counter proposal? He added women’ also must transmit body parts to offspring. If a woman is not pregnant than the body parts would bleed out with menstrual cycle. And seeds travels in the blood of man and woman. His sayings about the importance of blood still has its affects.

First hypothesis of inheritance Preformation hypothesis A tiny persons inside a sperm and egg. A tiny person inside a sperm, as drawn by Nicolaas Hartsoeker in 1695

William Harvey (1620) slaughtered the newly mated deer and looked into his uterus and could not see a formation with a stag inside. However, he continued his slaughterings in different time periods after conceptipn; and he saw the first embryo. After the microscope was discovered sperm and egg cells were visualised.

Pangenesis is one of the hypotheses put forward for heredity. It was first put forward by Hippocrates (BC 500 -400). Darwin later supported this hypothesis and published it. Darwin used this hypothesis to fill the gap in evolutionary studies. “Every part of the body constantly produces organic particles that are similar to itself. These particles are called gemules. The vessels are collected in gonads and transfer the inheritance information to gametes Pangenesis means originating from anywhere.

Mc. Comas, W. F. (2012). Darwin's invention: inheritance & the" mad dream" of pangenesis. The american biology Teacher, 74(2), 86 -91.

Pangenesis able to explain some inheritance issues like… By saying gemmules can stay dormant: recessive traits were explained. Gemmule helps with regeneration process. If an organ develops new specialties the old organs and the old gemmules were eaten by the new ones. New variations seen in the population were ascociated with the using or not using of the organ.

Proving Pangenesis is wrong Francis Galton (Half cousin of Darwin) tested the so called “gemmules travelling” in the blood. Took blood from Monrel rabbits and transferred the blood to agouthi grey rabbit. What did he expect? He expected a change in the further generations. because he transferred gemmules by blood transfusion. • Of course nothing has changed. Color and other specialities of the rabbits stayed as previous.

Weismann Germ plasma rule: It states that heritable information is transmitted only by germ cells in the gonads (ovaries and testes), not by somatic cells. Contrary to Lamarckism The related idea that information cannot pass from somatic cells to the germ line. The theory to some extent anticipated the development of modern genetics.

Are you familiar with this experiment ?

Blending theory The mixture of sperm and egg resulted in progeny that were a “blend” of two parent’s characteristics. Red flower white flower Pink flower

hypothesis of inheritance De Vries Mutation : He didn’t accept Pangenesis, but he wasn’t aware of Mendel’s studies. Holland tulip The encounter with tulips of different colors attracted the attention of the Dutch, who were trying to get dark red tulips. He bred evening glory plant and he explained the observed variations by mutation. Darwin called these rare occurrences "freaks". Than he rediscovered Mendel’s work.

hypothesis of inheritance

The organism receives developmental information from its parents. 1 - the argument for why offspring born look like parents. The similarity between Jackie and Selma. 2 - arguments about where factors related to heredity are located.

Mendel theory Mendel presented the particulates inheritance theory. He said that the characters were determined by the parts he called units and these units were carried over in generations. This theory explained many phenotypes. He defined the importance of these parts in heredity, which he called units in the 1860 s.

Epigenesis Epigenetics is presented by Conrad Hal Waddington. In the emergence of this term; Non-Mendelian inheritance, The formation of different cells from a zygote, Develo pm genetic ental biology, ist, emb p ryologis aleantologist, t and p hysiolo gist. https: //www. nature. com/articles/nrg 933

• Non-Mendelian kalıtım aynı genotip ama farklı fenotip Penetrance, Expressivity • Developmental biology from one cell to a whole organism!

Zygote development from one cell to an organism Zygote

HOW? How our cells differentiate? Why identical twins are not identical?

Epigenetic Greek prefix epi means above Epigenetics Epigenetic is the condition that the resulting phenotype or gene expression changes are not caused by changes in the DNA sequence; ü DNA methylation, ü Histone modification, ü Some non-coding RNAs

History Genetics is relatively new department when we compare it with other divisions. 1859 Discovery of Natural Selection by Charles Darwin. 1865 Discovery of hereditary transmitted in units by Gregor Mendel

Did they ever meet?

Mendel, pea 7 characters plant hybrids Roux-Weisman importance of chromosome in inheritance • Science community didn’t take into account, HARD TO UNDERSTAND! 1875– 1880 1865 1883 Cell and nucleus role put forth

1900 Correns, De Vries and Tschermak rediscovered Mendel’ principals. 1910 Morgan and Sturtvent “Chromosomal theory of inheritance” 1931 Mc. Clintock recombination event 1944: Oswald Avery, Colin Mac. Leod and Maclyn Mc. Carty showed that DNA (not proteins) can transform the properties of cells, demonstrating that DNA is the hereditary material. 1953 Structure of DNA

Discovery of Natural Selection by Charles Darwin What is the basis of evolution?

Discovery of Natural Selection by Charles Darwin It is actually really simple; ability to survive and reproduce. How are we able to survive and have ability to adapt? These abilities depend on genetic diversity.

Lets think, what would happen if genetic diversity don’t exist in species