Biology Ch9 Genetics Mendel

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www.soulcare.org Sid Galloway Chapter Nine Fundamentals of Genetics 9.1 Mendel’s Legacy 9.2 Genetic Crosses The Biology of Creation Studying God’s World (Science) in the Light of God’s Word (Scripture)Mr. Galloway

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www.soulcare.org Sid Galloway GENETICS is the field of Biology devoted to understanding how characteristics are transmitted from Parents to Offspring. Blending Concept of Inheritance (Before Mendel): This theory stated that offspring would possess traits intermediate between those of different parents. (Red and white flowers produce pink) Traits = different physical characteristics (like height, color, etc in pea plants)

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www.soulcare.org Sid Galloway Banded Water Snake

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www.soulcare.org Sid Galloway Gregor Mendel : Austrian monk who studied science and mathematics (statistics) and formulated two fundamental laws of heredity in the early 1860's.

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www.soulcare.org Sid Galloway Mendel's Garden Peas = Pisum sativum He used his knowledge of Statistics to analyze his observations of the seven characteristics of garden peas. Mendel traced inheritance of individual traits and kept careful records of numbers.

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway Mendel’s Methods : carefully controlling how the pea plants were Pollinated. Purebred = plants with traits that always produce offspring with that trait. Strain = plant (organism) that is pure for a specific trait Hybrid = the offspring of parent organisms that are purebred for different forms of one trait.

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www.soulcare.org Sid Galloway Parental P1 Generation = the parental generation in a breeding experiment. F1 generation is the first-generation offspring in a breeding experiment. (1st filial generation) From breeding individuals from the P1 generation. F2 generation is the second-generation offspring in a breeding experiment. (2nd filial generation) From breeding individuals from the F1 generation

Labeling Generations : 

www.soulcare.org Sid Galloway Labeling Generations

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www.soulcare.org Sid Galloway Mendel’s Conclusions: from statistical analysis he hypothesized that the traits must be carried by some form of “factors” that: Pairs is how they occur Segregate in gamete production (sperm / egg) Independently sort out from one another

Mendel’s Two Laws of Inheritance: : 

www.soulcare.org Sid Galloway Mendel’s Two Laws of Inheritance: Law of Segregation: Each organism contains two factors for each trait; factors segregate, or separate, in formation of gametes.  Law of Independent Assortment states that factors for different characteristics are distributed to gametes independently.

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Segregation & Independent Sorting : 

www.soulcare.org Sid Galloway Segregation & Independent Sorting

Modern Molecular Genetics Matches Mendel’s Predictions: : 

www.soulcare.org Sid Galloway Modern Molecular Genetics Matches Mendel’s Predictions: Sutton: (1903) used a microscope to discover that chromosomes were the factors Mendel predicted. A Gene is a segment of DNA on a Chromosome that controls a particular hereditary trait. Chromosomes occur in pairs, so genes also occur in pairs.

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway Alleles = several alternative forms of a gene. Mendel’s Factors are now called alleles. Letters are used to represent Alleles: Capitals refer to a Dominant Allele that masks or hides expression of a recessive allele. Lowercase refers to a Recessive Allele its expression is masked by a dominant allele.

Dominant vs. Recessive : 

www.soulcare.org Sid Galloway Dominant vs. Recessive Dominant Factor because it masked, or dominated the other factor for a specific trait Recessive Factor = the other trait that did not appear when paired with a dominant trait.

Examples of Symbols : 

www.soulcare.org Sid Galloway Examples of Symbols In pea plants, tall is dominant so a capital “T” is used for the dominant tall allele. Short is recessive so a lowercase “t” is used for the short allele. A purebred tall pea plant would be: TT A purebred short pea plant would be: tt A hybrid tall pea plant would be: Tt

9.2 Genetic Crosses : 

www.soulcare.org Sid Galloway 9.2 Genetic Crosses Genotype consists of the gene alleles that the organism inherits from its parents. Phenotype is the (physical phenomenon), that is the appearance that you can see in an organism as a result of its genotype. Homozygous is when both alleles of a pair are alike (TT) or (tt). Same as “purebred”. Heterozygous is when the alleles of a pair are different (Tt). Same as “hybrid”.

Probability : 

www.soulcare.org Sid Galloway Probability Probability is the likelihood that a specific event will occur or is the likely outcome a given event will occur from random chance. With each coin flip there is a 50% chance of heads and 50% chance of tails. Chance of inheriting one of two alleles from a parent is also 50%.

To Calculate Probability as Percentage : 

www.soulcare.org Sid Galloway To Calculate Probability as Percentage The number of times an event happened or expected to happen TOTAL number of opportunities for an event to happen 705 ___ = .76 = 76% Yellow 929 224 ___ = .24 = 24% White 929 If 929 offspring are produced, then that is the TOTAL number of opportunities If 705 offspring were yellow and 224 were white, then:

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www.soulcare.org Sid Galloway Monohybrid Cross is a cross between individuals that involves One Pair of Contrasting Traits * Example PP x pp Punnett Square is a tool to calculate probable results of a genetic cross. All possible types of sperm alleles are lined up vertical and all possible egg alleles are lined up horizontally, so that every possible combination can be shown in squares.

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www.soulcare.org Sid Galloway HOMOZYGOUS X HOMOZYGOUS Genotype Probabilities = 100% probability that the offspring will be (Tt)Phenotypes =100% probabilitythat all will be dominant (In thisexample: Purple)

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www.soulcare.org Sid Galloway HOMOZYGOUS X HETEROZYGOUSGenotype Probabilities = 50% TT and 50% Tt

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www.soulcare.org Sid Galloway HETEROZYGOUS X HETEROZYGOUSGenotype Probabilities = 25% BB25% bb 50% Bb

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www.soulcare.org Sid Galloway Complete Dominance is when one allele has complete dominance over another. Peas (T) tall dominant over (t) short Incomplete Dominance occurs when two or more alleles influence the phenotype, resulting in a phenotype intermediate between the dominant trait and recessive trait. Red flowers x White flowers produce Pink flowers Codominance occurs when both alleles for a gene are expressed in a heterozygous offspring. White guinea pig x black guinea pig produces a black and white offspring.

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www.soulcare.org Sid Galloway A testcross is used to determine the genotype of an unknown individual. There are different types of test crosses. Monohybrid Cross is a cross between individuals that involves One Pair of contrasting traits (Example = PP x pp) A dihybrid cross is a cross between individuals that involves TWO Pairs of contrasting traits. (Example = PPrr x ppRr)

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway

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www.soulcare.org Sid Galloway

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Dog Kind – no new info : 

www.soulcare.org Sid Galloway Dog Kind – no new info

Possible variation - dogs : 

www.soulcare.org Sid Galloway Possible variation - dogs

Possible variation - dogs : 

www.soulcare.org Sid Galloway Possible variation - dogs

Possible variation - dogs : 

www.soulcare.org Sid Galloway Possible variation - dogs

Possible variation - dogs : 

www.soulcare.org Sid Galloway Possible variation - dogs

Possible variation - dogs : 

www.soulcare.org Sid Galloway Possible variation - dogs

Possible variation - dogs : 

www.soulcare.org Sid Galloway Possible variation - dogs

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www.soulcare.org Sid Galloway Number of atoms in the Universe :1080

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www.soulcare.org Sid Galloway Number of electrons that can be fitted into the known Universe: 10130

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www.soulcare.org Sid Galloway Number of children from one couple without two exactly the same: 102017

Noah’s Ark – New Jan 2004 : 

www.soulcare.org Sid Galloway Noah’s Ark – New Jan 2004

Lotsa Dogs!!! W/circles : 

www.soulcare.org Sid Galloway Lotsa Dogs!!! W/circles

Lotsa Dogs!!! W/circles : 

www.soulcare.org Sid Galloway Lotsa Dogs!!! W/circles AB ab

Dog medium fur length : 

www.soulcare.org Sid Galloway Dog medium fur length

Dogs – Natural Selection Cold/Hot : 

www.soulcare.org Sid Galloway Dogs – Natural Selection Cold/Hot

Dogs – Natural Selection Cold/Hot : 

www.soulcare.org Sid Galloway Dogs – Natural Selection Cold/Hot

Wild dogs 1 : 

www.soulcare.org Sid Galloway Wild dogs 1 Aardwolf African wild dog Arctic fox Argentine gray fox Black-backed jackal Blanford’s fox Bat-eared fox Bush dog Wild dogs

Wild dogs 2 : 

www.soulcare.org Sid Galloway Wild dogs 2 Wild dogs Arctic wolf Cape fox Corsac fox Coyote Crab-eating fox Culpeo fox Dhole Fennec fox

Wild dogs 3 : 

www.soulcare.org Sid Galloway Wild dogs 3 Wild dogs Arctic fox Dingo Dingo Ethiopian wolf Falkland Island’s fox Golden jackal Tibetan sand fox Gray wolf

Wild dogs 4 : 

www.soulcare.org Sid Galloway Wild dogs 4 Wild dogs Gray fox Hoary zorro Kit fox Maned wolf Mexican gray wolf Raccoon dog Sand fox Small-eared dog

Wild dogs 5 : 

www.soulcare.org Sid Galloway Wild dogs 5 Wild dogs Pale fox Pampas fox Red fox Red wolf Sechuan zorro Timber wolf Iberian wolf

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www.soulcare.org Sid Galloway

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My Genius Dog: “Suzy” : 

www.soulcare.org Sid Galloway My Genius Dog: “Suzy”

Human Inheritance : 

www.soulcare.org Sid Galloway Human Inheritance My son, Michael, at the age of about six years old asked my wife: “Mom, why do all six of us kids look like both you and Dad?” She said: “God takes a little bit of me and a little of Dad to make each of you.” After looking puzzled and concern, Mike responded: “Wow, then there must not be much of ya’ll left after six kids.”

Single Gene Traits = : 

www.soulcare.org Sid Galloway Single Gene Traits = traits that are controlled by just one gene (with two alleles). * Examples: 1. Mendel’s peas 2. Human Hairline: “widow’s peak”

Widow’s Peak Hairline : 

www.soulcare.org Sid Galloway Widow’s Peak Hairline

Multiple Alleles : 

www.soulcare.org Sid Galloway Multiple Alleles = three or more forms of a single gene that code for a single trait. * Only two alleles can be carried on a gene, since chromosomes exist in pairs. * Each chromosome carries only one allele for each gene. But there can be many possible forms of the alleles. Example = human blood type (A, B, AB, O) - Three alleles control inheritance of blood types. - A and B are codominant. , but O is recessive. A = IA B= IB O = i

Blood Types : 

www.soulcare.org Sid Galloway Blood Types

The test for blood type : 

www.soulcare.org Sid Galloway The test for blood type

Multiple Gene Traits : 

www.soulcare.org Sid Galloway Multiple Gene Traits are controlled by many genes acting together as a group to produce the visible phenotype. * Human skin color is controlled by at least three genes. - Each skin gene has at least two possible alleles at that gene site on the DNA. - The allele combinations determine the amount of pigment in the skin cells.

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Environmental Effects : 

www.soulcare.org Sid Galloway Environmental Effects – The organism’s surroundings can alter the effect of the genes. * Example: Diet can affect height. - Since 1800’s human height has increased by 10 cm on average.

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www.soulcare.org Sid Galloway Sex-Linked Genes are alleles that are passed from parents to a child on a sex chromosome. * Sex-linked genes can be dominant or recessive. * Since males have only one X chromosome, males are more likely than females to have a sex-linked trait that is controlled by a recessive allele. Why? Because they do not have another X to carry a dominant allele that could cover or masks the recessive allele. * Red-Green color blindness is an example of a sex-linked trait.

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www.soulcare.org Sid Galloway A CARRIER is a person who has one recessive allele for a trait and one dominant allele. The dominant allele masks the recessive allele so the trait does not show up. But the carrier can pass the recessive allele on to offspring.

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www.soulcare.org Sid Galloway Pedigree is a chart or “family tree” that tracks which members of a family have a particular trait.

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www.soulcare.org Sid Galloway Human Genetic Disorders Genetic Disorder = an abnormal condition that a person inherits through genes or chromosomes. * They are caused by mutations, which are changes in a person’s DNA.

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www.soulcare.org Sid Galloway Cystic Fibrosis = the lungs and intestines fill with mucus. Sickle-Cell Disease = red blood cells are shaped like sickles. Hemophilia = causes the blood to clot too slowly or not at all. Huntington’s Disease = causes the breakdown of brain cells. Down Syndrome = an extra copy of chromosome number 21.

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www.soulcare.org Sid Galloway Diagnosing Genetic Disorders Amniocentesis is now used. - Long needle to get fluid and cells from the baby in the mother’s womb. - A karyotype (a picture of all the chromosomes in the baby’s cell) is then made and examined by the doctor. Genetic Counseling by doctors, helps families predict the possibilities of having a child with the disorder.

Karyotype : 

www.soulcare.org Sid Galloway Karyotype

Advances in Genetics : 

www.soulcare.org Sid Galloway Advances in Genetics Three Methods to Produce Organisms with desirable traits: Selective Breeding Cloning Genetic Engineering

Selective Breeding : 

www.soulcare.org Sid Galloway Selective Breeding A process where scientists select a few organisms with desired traits to serve as parents of the next generation. Inbreeding = crossing two individuals that have similar sets of alleles. (Used to produce purebred dogs.) Hybridization = crossing two genetically different individuals. (Used to mix two different desirable traits.) (Like corn that has lots of kernels & is healthy.)

Cloning : 

www.soulcare.org Sid Galloway Cloning copying one organism to make another one from it, that has exactly identical genes. a. Plants are cloned by planting a cutting (a small part of stem or leaf) to grow a another plant just like the original. b. Animals are cloned, like Dolly the sheep, are made by taking an egg from one sheep and replacing its nucleus the nucleus from another sheep. The egg then grows into a copy of the sheep with that nucleus.

Genetic Engineering : 

www.soulcare.org Sid Galloway Genetic Engineering A process where genes from one organism are transferred into the DNA of another organism. It is also called “gene splicing”. Scientists sometimes use viruses to transfer the DNA. Gene Therapy is a process that tries to correct genetic disorders, by inserting normal (working) copies of the gene into the cells of a person with a disorder. Genome is a word that for ALL the DNA in one cell or an organism.

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