460 likes | 600 Views
Mendelian genetics. Gregor Mendel. Father of modern genetics Researched with pea plants. Gregor Mendel. Father of modern genetics Researched with pea plants Developed ideas of dominance and trait segregation. Beberapa Istilah Yang sering digunakan.
E N D
Gregor Mendel • Father of modern genetics • Researched with pea plants
Gregor Mendel • Father of modern genetics • Researched with pea plants • Developed ideas of dominance and trait segregation
Beberapa Istilah Yang sering digunakan • parental (P): induk/ orangtua (parents) • filial (F) : keturunan (misal F1 adalahketurunanpertama, F2 keturunankedua) • fenotip : karakterindividu yang dapatdiamati, misalbentuk, warna, danukuran • genotip : susunangenetiksuatuindividu (gabungan gen), biasanyaditulisdengan simbolhurufdobel, misalnya AA, BB, cc, dddanseterusnya • alel : pasangan gen (misal, gen M menentukanwarnamerah, danalelnya mmenentukanwarnaputih). M aleldominan, m alelresesif
Beberapa Istilah Yang sering digunakan • Homozigot : sifatsuatuindividu yang genotipnyaterdiridarialel-alel yang samauntuktiapjenis gen. Contoh : RR, rr, AABB, aabbdan lain-lain • Heterozigot : sifatsuatuindividu yang genotipnyaterdiridarialel-alel yang berlainandaritiapjenis gen. Contoh : Rr, AaBbdan lain-lain • Hibrid : perkawinanantaraduaindividu yang memilikisifatbeda (monohibrid : satusifatbeda, dihibrid : duasifatbeda) • Persilanganresiprok : persilangan yang merupakankebalikandaripersilangan semula • Persilangankembali (backcross) : persilanganantarahibrid F1 denganinduknyajantanataubetina • UjiSilang (testcross) : persilanganantarahibrid F1 denganindividu yanghomozigotresesif
Phenotype • Phenotype • Physical characteristics
Genotype • Phenotype • Physical characteristics • Genotype • Genes we inherit from our parents
Phenotype • Facial structure Notice the similarities:
Phenotype • Facial structure • Eyes Notice the similarities:
Phenotype • Facial structure • Eyes • Smile Notice the similarities:
Phenotype • Facial structure • Eyes • Smile • Ears Notice the similarities:
Phenotype • Facial structure • Eyes • Smile • Ears • Nose Notice the similarities:
Phenotype • Facial structure • Eyes • Smile • Ears • Nose • Neck Notice the similarities:
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL • Seed color - green or YELLOW
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL • Seed color - green or YELLOW • Seed shape - wrinkled or ROUND
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL • Seed color - green or YELLOW • Seed shape - wrinkled or ROUND • Seed coat color - white or GRAY
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL • Seed color - green or YELLOW • Seed shape - wrinkled or ROUND • Seed coat color - white or GRAY • Pod shape - constricted or SMOOTH
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL • Seed color - green or YELLOW • Seed shape - wrinkled or ROUND • Seed coat color - white or GRAY • Pod shape - constricted or SMOOTH • Pod color - yellow or GREEN
Mendelian Genetics • Mendel studied a number of characteristics in pea plants including: • Height - short or TALL • Seed color - green or YELLOW • Seed shape - wrinkled or ROUND • Seed coat color - white or GRAY • Pod shape - constricted or SMOOTH • Pod color - yellow or GREEN • Flower position - terminal or AXIAL
Mendelian Genetics • We will work with the following three: • Height - short or TALL • Seed color - green or YELLOW • Seed shape - wrinkled or ROUND • Seed coat color - white or GRAY • Pod shape - constricted or SMOOTH • Pod color - yellow or GREEN • Flower position - terminal or AXIAL
Mengapa penelitian Mendel menggunakan kacang Ercis? • berumurpendek, mudahtumbuhdanmudahdisilangkan • memilikibungasempurna (memilikibenang sari danputik) • dapatmelakukanpenyerbukansendiridandapatdisilangkandenganbantuan manusia • memilikivariasi karakter(7) denganperbedaan yang menyolok (batang, warnapolong, teksturpolong, warnabunga, letakbunga, warnabiji, danpermukaanbiji).
Predicting Inheritance To determine the chances of inheriting a given trait, scientists use Punnett squares and symbols to represent the genes. UPPERCASE letters are used to represent dominant genes. lowercase letters are used to represent recessive genes.
Predicting Inheritance For example: T = represents the gene for TALL in pea plants t = represents the gene for short in pea plants So: TT & Tt both result in a TALL plant, because T is dominant over t. t is recessive. tt will result in a short plant. Remember there are two genes for every trait! One from each parent.
Predicting Inheritance For example: T = represents the gene for TALL in pea plants t = represents the gene for short in pea plants So: TT &Ttboth result in a TALL plant, because T is dominant over t. t is recessive. tt will result in a short plant. Remember there are two genes for every trait! Mendels’ Principle of Dominance Some genes (alleles) are dominant and others are recessive. The phenotype (trait) of a dominant gene will be seen when it is paired with a recessive gene.
Predicting Inheritance Let’s cross a totally dominant tall plant (TT) with a short plant (tt). Each plant will give only one of its’ two genes to the offspring or F1 generation. TT x tt T T t t
Predicting Inheritance Let’s cross a totally dominant tall plant (TT) with a short plant (tt). Each plant will give only one of its’ two genes to the offspring or F1 generation. TT x tt Mendels’ “Law” of Segregation Each gene (allele) separates from the other so that the offspring get only one gene from each parent for a given trait. T T t t
Punnett Squares The genes from one parent go here. The genes from the other parent go here.
Punnett Squares F1 generation
Interpreting the Results The genotype for all the offspring is Tt. The genotype ratio is: Tt - 4/4 The phenotype for all the offspring is tall. The phenotype ratio is: tall - 4/4
Punnett Squares Your Turn!!
Punnett Squares F2 generation
Punnett Squares Next, give the genotype and phenotype ratios of the offspring (F2 generation).
Punnett Squares Genotype ratio: TT - 1
Punnett Squares Genotype ratio: TT - 1, Tt - 2
Punnett Squares Genotype ratio: TT - 1, Tt - 2, tt - 1
Punnett Squares Genotype ratio: TT - 1, Tt - 2, tt - 1 Phenotype ratio: Tall - 3
Punnett Squares Genotype ratio: TT - 1, Tt - 2, tt - 1 Phenotype ratio: Tall - 3, short - 1
Punnett Squares This is a monohybrid cross. We worked with only one trait. The height of the plant.
Punnett Squares This is a monohybrid cross. We worked with only one trait. The height of the plant. two Later we will work with a dihybrid cross, using the height of the plant and either seed color or seed shape.