1. Genetics Genetics

2. Genetics Is the science of heredity. Heredity is the transmission of genetic or physical traits from parent to offspring.

3. Gregor Mendel Austrian Monk Considered the “Father of Heredity” He conducted plant breeding experiments in their monastery garden. In 1865 he made his work public, units of inheritance.

4. What makes us unique? Each of the 100 Trillion cells in our body except the red blood cells contains the entire human genome, in the nucleus of every cell is the genetic information “blueprint” to construct the individual. It is the Deoxyribonucleic acid (DNA) Function of DNA – Genetic code for almost every organism. – Provide template for protein synthesis.

5. Chromosomes The DNA in every cell is located in rod like segments called chromosomes Chromosomes occurs in pairs in every cell of our body except in the sperm and ovum. Chromosomes numbers are the same for each specie.

6. Chromosome Numbers SpecieDiploid #Haploid # Cattle6030 Swine3819 Sheep5427 Horse6432 Human4623 Chicken7839 Goat6030 Donkey6231

7. Chromosomes There are 2 sex chromosomes included in the diploid number of the chromosomes. All of the other chromosomes are referred to as autosomes. In mammals if the sex chromosomes are alike, XX it results in a female. If the sex chromosomes are different, XY it results in a male.

8. Sex Determination Female can contribute only a X chromosome towards the sex of their offspring. Male can contribute an X or a Y chromosome toward the sex of their offspring. Absence of an Y chromosome results in a the embryo developing into a female. Presence of an Y chromosome results in the embryo developing into a male.

9. Tell me what I am ?????

11. Genes Chromosomes contains several units of inheritance “genes”. Genes usually occurs in pairs, one from each parent. Some traits are inherited directly from one set of genes. Some traits are inherited through several sets of genes.

12. Terms to know Homozygous- contains 2 identical genes for the same trait, AA, BB, cc Heterozygous- contains 2 different genes for the same trait, Aa, bB, Cc Phenotype- Outward appearance of a trait, coat color, polled, horned. Genotype- Genetic classification of a gene, AA, Aa, aa. Allele- Location of a gene on the chromosome. F-one = First cross mating. F-two = Second cross mating.

13. What are dominant genes? The gene that express itself, the powerful and dominant gene. It has the power to overshadow the recessive gene when there is complete dominance. Some examples are: – White faced in cattle – Droopy ears in swine – Polled in cattle – Black coat color in Angus cattle

14. What are Recessive Genes ? The gene that is overshadowed by a dominant gene Recessive genes can only express themselves in the absence of the dominant gene Polled vs Horned (Pp) (pp) Black wool vs white (Ww) (ww) Dwarfism vs normal size (dd) Albino

15. Punnet Square Angus- Black coat color is dominant. BB = Homozygous Dominant and Black Bb = Heterozygous and is black bb = Homozygous recessive and red A heterozygous bull is mated to 50 homozygous recessive cows. How many calves are black? How many calves are red? What is the genotypic and phenotypic ratios?

16. Punnet Square

17. Results 2 heterozygous = Bb 2 Homozygous Recessive bb 25 Black, 25 Red Genotypic ratio = 0:2:2 Phenotypic ratio = 2 Black: 2 Red

18. What are Sex Linked Genes ? Some recessive genes are attached to the X and Y chromosomes Humans: Colorblindness and Baldness are on the X chromosomes In Men, traits expressed anytime present In Women, must have two recessives to show trait Children get baldness from mothers

19. What is Incomplete Dominance ? If both genes express themselves Shorthorn Cattle: Red male mated to a White female = Roan calf RR crossed rr = Rr

20. What is a Mutation ? Dramatically different from what is expected genetically Horned calf from polled parents Loss of some or extra body parts Lethal Mutation : causes death at birth Sublethal Mutation : limits animals ability to grow to maturity Beneficial Mutation: loss of tail in lambs

21. Monohybrid Crosses Cross 1 character – Flower Color Purple Flowers are dominant – P White Flowers are recessive – p Cross a Heterozygous with a homozygous recessive Genotype Ratio: 2 Pp; 2 pp Phenotype Ratio: 2 Purple 2 White Probabilities: Being Purple: 2 out of 4 Being White: 2 out of 4 Cross: Pp X pp Pp p p Pppp Pppp

22. Pedigrees A family history that shows how a trait is inherited over several generations Helps to track down the carriers (heterozygotes) of recessive disorders. Reading Pedigrees  A shaded box –affected male …………  A shaded circle- affected female……….  A clear box- normal male…………..  A clear circle- normal female………...

23. Pedigree Practice ? I II III IV ? Legend: Hemophilic Male: ……… Hemophilic Female: …... Normal Female: ……… Normal Male: ………

24. Codominance Case in which both forms of the character are displayed. Ex. The ABO blood groups  Neither I A nor I B are dominant is dominant over the other.  Both are dominant over i (Type O).  When both I A and I B are present they are codominant and the individual is type AB

25. Blood Typing iiIBiIBiIAiIAi IBiIBiIBIBIBIB IAIBIAIB IAiIAiIAIBIAIB IAIAIAIA I A I B i IAIBiIAIBi OBABA Blood Types