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Pertemuan ke-8 Hereditas dan Variasi Oleh: Dwi Kusuma Wahyuni, S.Si., M.Si. Departemen Biologi Fakultas Sains dan Teknologi Universitas Airlangga.

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Presentasi berjudul: "Pertemuan ke-8 Hereditas dan Variasi Oleh: Dwi Kusuma Wahyuni, S.Si., M.Si. Departemen Biologi Fakultas Sains dan Teknologi Universitas Airlangga."— Transcript presentasi:

1 Pertemuan ke-8 Hereditas dan Variasi Oleh: Dwi Kusuma Wahyuni, S.Si., M.Si. Departemen Biologi Fakultas Sains dan Teknologi Universitas Airlangga

2 Sub Topik  Hereditas  Sumber-Sumber Variasi Genetik  Gen Dalam Evolusi: pengaturan variasi  Pengukuran Variasi  Variasi dan Struktur Populasi

3 Individu di dunia ini sangat bervariasi, ada banyak karakter yang bervariasi di dalamnya Ada populasi monomorfik dan ada populasi polimorfik Pengantar

4 Heriditas Vs Heritabilitas

5 Heriditas adalah proses penurunan sifat dari induk ke keturunannya baik secara biologis melalui gen atau secara sosial melalui pewarisan gelar atau status sosial Dalam pertemuan ini akan dipelajari hereditas secara biologi terkait dengan mekanisme evolusi Heriditas

6 Heritabilitas  Karakter individu yang diturunkan dari satu generasi ke generasi berikutnya  Diukur sebagai proporsi variasi suatu sifat dalam suatu populasi yang dinyatakan sebagai variasi gen

7 Central Dogma GGGG S SS S DDDD P PP P A B Reproduksi Tumbuh Replikasi Transkripsi Translasi

8 Genetic Terminology  Heterozygote and homozygote  Zygote and gamete  Gene, allele, locus, and chromosome  Dominant and recessive  Blending inheritance  Particulate inheritance  Genotype and phenotype  Heterozygote and homozygote  Zygote and gamete  Gene, allele, locus, and chromosome  Dominant and recessive  Blending inheritance  Particulate inheritance  Genotype and phenotype

9 DNA and Modern Genetics Human karyotype, 2N = 46 (female) James Watson & Francis Crick The DNA molecule Fertilization

10 Watson & Crick Double Helix  Nucleotides made up of sugars, phosphates, and nitrogenous bases  Hydrogen bonds between complementary bases  A and G  T and C  Information resides in linear sequence of bases on one of the strands  Nucleotides made up of sugars, phosphates, and nitrogenous bases  Hydrogen bonds between complementary bases  A and G  T and C  Information resides in linear sequence of bases on one of the strands

11 DNA Replication  How do chromosomes copy themselves during cell division?  DNA double helix unzips, and forms template for replication  Nucleotides come in and pair off in complementary fashion fashion to create two double helices, identical to the original  How do chromosomes copy themselves during cell division?  DNA double helix unzips, and forms template for replication  Nucleotides come in and pair off in complementary fashion fashion to create two double helices, identical to the original

12 Protein Synthesis  How do genes make proteins?  Transcription is copying of DNA info onto mRNA  mRNA then travels to ribosome  Translation is production of a polypeptide  tRNA brings in amino acids in appropriate sequence  Amino acids are linked by peptide bonds to form protein  Complementary base pairing occurs at every step of the process  How do genes make proteins?  Transcription is copying of DNA info onto mRNA  mRNA then travels to ribosome  Translation is production of a polypeptide  tRNA brings in amino acids in appropriate sequence  Amino acids are linked by peptide bonds to form protein  Complementary base pairing occurs at every step of the process transcription translation

13 The Genetic Code  Triplet code, each triplet of bases codes for a single amino acid  Code is redundant and universal  Evidence of single ancestry of life on Earth  Mutations are mistakes in some step of this process  Triplet code, each triplet of bases codes for a single amino acid  Code is redundant and universal  Evidence of single ancestry of life on Earth  Mutations are mistakes in some step of this process

14 What are genes? Genes: discrete subunit of chromosome, carry genetic information Chromosomes: the threadlike structures where DNA is contained DNA: Deoxyribonucleric acid. All DNA is composed of the same 4 nucleotide (ATGC), differ in sequence. Alleles: alternate forms of a gene (A, a). Locus: the position of an allele occupies on a chromosome Homozygous (AA, aa) vs heterozygous (Aa) Dominance (A vs a), incomplete dominance (Aa shows different trait to AA or aa)

15 Genotype: the sum of genes carried by the individual. Gene pool: total collection of genes across all individual in the population at any one time Phenotype: the observed expression of genotype (color etc) How are genes transmitted?

16 Phenotypic plasticity Phenotypic plasticity: the ability of a genotype to give a range of phenotypic expressions under different environmental conditions.

17 Variasi Genetik Adalah Bahan Seleksi Alam Variasi genetik dalam suatu populasi adalah sangat penting untuk terjadinya seleksi alam Jika semua individu-individu dalam suatu populasi adalah sama maka kecocokannya terhadap lingkungan juga akan sama Jika semua individu-individu dalam suatu populasi adalah sama maka kecocokannya terhadap lingkungan juga akan sama

18  Sumber-Sumber Variasi Genetik 1. Mutasi: peubahan-perubahan pada gen dan kromoson yang dapat diturunakan  Mutasi Gen: (point mutation: frameshift mutation and base substitution),  Mutasi Kromosom  deletion, duplication, inversion, translocation, poliployd 2. Recombinasi Genetik

19 4. Reproduksi Seksual: dua individu memproduksi gamet ( ovum dan sperma) yang dikombinasi gamet ( ovum dan sperma) yang dikombinasi menjadi sel diploid atau sigot menjadi sel diploid atau sigot Percampuran gen melalui gamet dari kedua induknya diturunkan pada keturunannya Peningkatan variasi populasi secara dramatik terjadi karena kombinasi baru gen-gen yang eksis 5. Reproduction aseksual: sedikit variasi (hanya mutasi)

20 Gen-Gen Dalam Populasi: Pengaturan Variasi

21 Evolusi adalah perubahan pada frekuensi gen  Evolusi adalah suatu perubahan frekuensi gen dalam populasi ( atau spesies) sepanjang waktu  Individu-individu tidak berkembang, populasi berkembang  Fokus pada gene pool, kolektif  Tetapi kenapa kita melihat populasi-populasi masih terlihat “sama” untuk beberapa generasi????

22 The Hardy-Weinberg Principle  The Hardy-Weinberg Principle: Gene frequencies will remain the same in successive generations of a sexually reproducing population if the following five conditions hold:  Random mating  There is no mutation  The population is very large  There is no selection  There is no migrations (isolated from other populations)

23 The Hardy-Weinberg Principle

24 Pengukuran Evolusi 1. Pengukuran Variasi Pada karakter-karakter fenotif 2. Pengukuran Heritabilitas : variasi genetik variasi fenotif total 3. Pengukuran Variasi Genetik: Elektroforesis, Teknik Imunologi, Sequencing Asam Amino, Sequencing DNA, Analisis RLFP, Analisis RAPD, DNA finger printing, DNA hybridization

25 Variasi dan Struktur Populasi  Variasi Genetik yang ada dalam suatu populasi (gene pool)  Natural Selection  Inbreeding effects  Genetic Drift  Founder effect  Genetic bottleneck  Inbreeding Depression


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