Chapter 10 HOW INHERITED TRAITS ARE TRANSMITTED. Genetics is the science of heredity.

Slides:



Advertisements
Similar presentations
Chapter 14~ Mendel & The Gene Idea
Advertisements

Mendelian Patterns of Inheritance
Mendelian Genetics 11.1 Gregor Mendel. Who was Gregor Mendel?  Austrian monk  Also “high school” science/math teacher  One of the first to use statistics.
Chapter 9 Patterns of Inheritance
GENETICS. Mendel and the Gene Idea Genetics The study of heredity. The study of heredity. Gregor Mendel (1860’s) discovered the fundamental principles.
Ch. 11 Outline – Mendelian Inheritance
Chapter 14: Mendelian Genetics!!. Trait : some aspect of an organism that can be described or measured Gene : discrete unit of hereditary information.
Mendelian Inheritance Chapter 11. Mendelian Inheritance 2Outline Blending Inheritance Monohybrid Cross  Law of Segregation Modern Genetics  Genotype.
Textbook Chapters Review Book Topic 3
Biology, 9th ed,Sylvia Mader
Genetics Chapter 11.
Patterns of Inheritance Chapter Early Ideas of Heredity Gregor Mendel -chose to study pea plants because: 1. other research showed that.
Mendel & Genetics Review Powerpoint
Mendel performed cross-pollination in pea plants.
Genetics.
Mendel, Genes, and Inheritance Chapter 12. Gregor Mendel Austrian Monk with a strong background in plant breeding and mathematics Using pea plants, found.
Mendelian Patterns of Inheritance Chapter 9. Introduction Gazelle always produce baby gazelles, not bluebirds.
Gregor Mendel Humans have noticed family resemblances for thousands of years. Heredity- the passing of traits from parents to offspring, was used for.
Patterns of Inheritance Inheritance Hypotheses Blending Hypothesis – parental contributions combined Particulate Hypothesis – parents pass along discrete.
Genetics and the Work of Gregor Mendel
GENETICS. The scientific study of heredity Heredity: the passing down of traits from parents to offspring via genes and chromosomes.
Mendel & heredity mysteries-at-the-museum/video/blue- people-roaming-the-hills.
 Heredity  The passing of traits from parents to offspring  The traits you have resemble your parents  These traits can include ◦ Eye color ◦ Shape.
Mendelian Genetics Blue People of Kentucky Methemoglobinemia.
Chapter 14: Mendel & The Gene Idea Quantitative approach to science Pea plants Austrian Monk.
 Genetics – the scientific study of heredity  Why the garden pea?  Easy to grow  Produce large numbers  Mature quickly  Reproductive organs in same.
Genetics.
Patterns of Inheritance
Mendel & Genetics Review Powerpoint Gregor Mendel, the father of genetics.
Chapter 11 HOW INHERITED TRAITS ARE TRANSMITTED. Genetics is the science of heredity.
The study of inheritance of traits.  Austrian Monk  Studied how traits were passed from parent to offspring  His ideas forms the foundation for the.
Heredity is the passing of characteristics from parents to offspring Trait – a characteristic that is inherited Example: –Hair color is a characteristic.
Chapter 14. Mendel and Heredity  Gregor Mendel – Austrian Munk  Worked with heredity in pea plants  Wanted to determine how characters and traits were.
1 A Tale of Two Families Modes of inheritance are the patterns in which single-gene traits and disorders occur in families Huntington disease is autosomal.
Probability  The principles of probability can be used to predict the outcomes of genetic crosses  Think of probability like flipping a coin. If you.
Introduction to Genetics and Heredity
Mendelian Heredity (Fundamentals of Genetics) Chapter 9
Why we look the way we look...
Chapter 8 Heredity.
Genetics Heredity – the passing of traits from parent to offspring
Mendel & heredity.
Mendel & the Gene Idea.
Ch. 8 Test Review Mendel and Heredity.
Unit 7 Genetics.
Mendel’s Laws of Heredity
Do Now What does the term “heredity’ mean?
Genetics Jeopardy!.
Genetics 101.
Mendel & The Gene Idea Chapter 14
Chapter 11 Mendel & Heredity.
MENDEL AND THE GENE IDEA
MENDEL AND THE GENE IDEA
Chapter 8 Mendel, Peas, and Heredity
Mendelian Genetics.
Punnett Squares.
HOW INHERITED TRAITS ARE TRANSMITTED
Lecture # 6 Date _________
Unit 6 “Genetics” 18 Words.
Mendel and Heredity Source:
Mendel’s Laws of Heredity
Why we look the way we look...
Biology.
Chapter 13: Patterns in Inherited Traits
Mendelian Genetics Mr. Davis.
Gregor Mendel: Father of Genetics
Mendel & Heredity.
Lecture # 6 Date _________
MENDEL AND THE GENE IDEA
Chapter 11: Introduction to Genetics 11-1 The Work of Gregor Mendel
Presentation transcript:

Chapter 10 HOW INHERITED TRAITS ARE TRANSMITTED

Genetics is the science of heredity.

Gregor Mendel ] Austrian monk with a strong mathematical background. ] Interested in how certain traits were passed from parents to offspring. ] Worked with pea plants ( ): F easy to grow & developed quickly F exhibited many traits that had 2 easily distinguishable forms F could manipulate fertilizations

Traits Mendel Studied

Mendel’s Experimental Approach for Breeding Peas

Mendel’s observations: ] Some pea plants were always “true breeding” (all offspring exhibit same trait as parents). short x short  all short offspring tall x tall  all tall offspring OR  some tall, some short ] One form of a trait tended to “mask” expression of the other form. tall x short  all tall offspring OR  some tall, some short

A tall x short mating never resulted in all short offspring. Thus, the tall trait masked expression of the short trait. Based upon these & subsequent observations, Mendel formulated the two basic laws of heredity: F Law of Segregation F Law of Independent Assortment

A. Genetic Terminology 1. Chromosome - dark staining body in a cell’s nucleus; consists of DNA & proteins. F haploid cells - 1 set of chromosomes F diploid cells - 2 sets of chromosomes 2. Gene (elementen) - a sequence of DNA that codes for production of a specific protein. Ex. stem length gene, seed color gene

3. Allele - an alternate form of a gene. Ex. stem length gene has 2 alleles - tall allele & short allele ] Dominant allele - allele that masks the expression of another allele. Ex. tall allele (T) ] Recessive allele - allele whose expression is masked by another allele. Ex. short allele (t)

Diploid organisms possess 2 alleles for each gene. 2 dominant alleles for gene ‘A’ 1 dominant & 1 recessive allele for gene ‘B’ 2 recessive alleles for gene ‘D’

If the 2 alleles are identical, then organism is homozygous for that gene. Ex. TT (homozygous dominant) tt (homozygous recessive) If the 2 alleles are different, then organism is heterozygous for that gene. Ex. Tt

4. Genotype - the allele combination in an individual. Ex. three possible genotypes for pea plant height: TT, Tt or tt 5. Phenotype - the observable expression of an allele combination. Ex. two possible phenotypes for pea plant height: tall or short

If you know an individual’s phenotype, do you automatically know their genotype? ] Yes, if the trait is recessive F short pea plants must be tt F round-seeded plants must be rr ] No, if the trait is dominant F tall pea plants can be either TT or Tt F wrinkled-seeded plants can be either RR or Rr

B. Law of Segregation The alleles of a gene separate during meiosis as chromosomes are packaged into gametes.

We use a Punnett square to predict the outcome of a cross between two individuals. Phenotypic ratio 3 tall : 1 short Genotypic ratio 1 TT : 2 Tt : 1 tt

We use a test cross to determine an unknown genotype. Test cross = a cross between an individual of unknown genotype and an individual that is homozygous recessive for the trait in question.

You are given a tall pea plant… determine it’s genotype. Do a test cross: tt x unknown F if all offspring are tall, THEN… unknown genotype is TT F if obtain both tall & short offspring, THEN… unknown genotype is Tt tt TT tt Tt Tt Tt tt

Mendelian Disorders in Humans: Autosomal Recessive Traits: F located on non-sex chromosomes F parents are carriers or are affected F affected individuals are homozygous recessive F affects males & females Ex. Albinism, Cystic fibrosis, Phenylketonuria, Sickle cell disease

Autosomal Dominant Traits: F located on non-sex chromosomes F at least one parent is affected F does not skip generations F affected individuals are homozygous dominant or heterozygous F affects males & females Ex. Achondroplasia, Huntington disease, Lactose intolerance, Polydactyly

Autosomal dominant pedigree

C. Law of Independent Assortment The segregation of one gene pair does not influence the segregation of another gene pair during meiosis.

D. Factors Appearing to Violate Mendel’s Laws 1. Lethal Alleles - certain allele combination causes death of an entire phenotypic class very early in development. Ex. hairless trait in dogs [homozygous dominant (HH) individuals die as embryos]

2. Multiple Alleles - gene exists as more than two alleles in the population. F Rabbit coat color gene has 4 alleles: C, c, c ch & c h 5 phenotypes 10 genotypes

3. Epistasis - one gene masks the expression of another. Ex. Bombay phenotype (H gene masks expression of I gene)

4. Incomplete Dominance - heterozygote expresses a phenotype intermediate between those of the two homozygotes. Ex. snapdragon flower color If cross Rr x Rr … Phenotypic ratio -> 1 red : 2 pink : 1 white Genotypic ratio -> 1 RR : 2 Rr : 1 rr

5. Codominance - heterozygote expresses a phenotype that is distinct from and not intermediate between those of the two homozygotes. Ex. Human AB blood type

E. Complex Traits Traits that do not follow Mendel’s laws, but tend to “run in families”. 1. Polygenic Traits - determined by the combined effect of more than one gene. Ex. height, eye color & skin color

Human Skin Color

2. Multifactorial Traits - determined by the combined effect of one or more genes plus the environment. Ex. heart disease, body weight, intelligence