Unit 3 Notes on Human Variation PDF

**Models of Human Variation** **Classification of Human Populations** +-----------------------+-----------------------+-----------------------+ | **Blumenbach** | **Deniker** | **Hooton** | +=======================+=======================+=======================+ | **i)...

**Models of Human Variation** **Classification of Human Populations** +-----------------------+-----------------------+-----------------------+ | **Blumenbach** | **Deniker** | **Hooton** | +=======================+=======================+=======================+ | **i)Caucasian | **i)Wooly hair,Broad | i)Caucasoid (Europe, | | White(Europe,Middle | nose** | North Africa, and | | East,South Asian)** | | Western Asia), | | | **ii)Curly or wavy | ii)Mongoloid (East | | **ii)Mongolian | Hair** | Asia), iii)Negroid | | Yellow** | | (sub-Saharan Africa), | | | **iii)Wavy | iv)Australoid | | **( Eastern Asia)** | brown,black hair,dark | (Australia, New | | | eyes** | Guinea, and Southeast | | **iii)Malay Brown** | | Asia). | | | **iv)Fair | | | **(SoutheastAsian, | wevy,straight hair** | | | Pacific Island)** | | | | | **v)Straight or wevy | | | **iv)Ethiopian | hair,dark black | | | Black** | eyes** | | | | | | | **( Sub Sahara)** | **vi)Straight hair** | | | | | | | **v)American Red** | | | | | | | | **(America)** | | | +-----------------------+-----------------------+-----------------------+ *[Twin genetics]* is the study of the genetic and environmental factors that contribute to the similarities and differences between twins. *[Sib-pair methods]* involve the analysis of genetic data from siblings to identify genetic variants associated with specific traits or diseases. **Mode of Inheritance** **Autosomal dominant**:A single copy of the dominant allele is enough to express the trait. **i)Huntington\'s disease( brain nervous) 4** **ii)Achondroplasia(short limb dwarfism) 4** **iii)Brachydactly (short finger)** **iv)Polydactly(extra finger)** **v)Porphyria(skin related)** **vi)Marfan (tissue) 15** **Autosomal recessive:**The **two copies of the recessive allele need to express the trait** **i)Cystic fibrosis(respiratory) Chromosome no 7** **ii)Sickle cell anemia (Hameoglobin) 11** **iii)Thalassemia(Hameoglobin) 16** **iv)Phenylketonuria (PKU) break down the amino acid phenylalanine 12** **v)Tay-Sachs disease(nervous system) 15** **vi)Mucolipidosis IV 19** **vii)Alpha-1 antitrypsin deficiency 14** **Autosomal Codominance:Both alleles have an equal effect on the expression of the trait.** **i)ABO blood group** **ii)Malaria Resistance (HbS,HbA),** **iii)PTC Tasting( phenylthiocarbamide-taster and non taster)** **iv). Free Earlobe(shape of the)** **v) Rh Blood Type(RR, Rr, and rr)** **Standard karyotyping and banding techniques**: G, C, and Q bands **Karyotyping technique** Tjio and Levan in 1956 **G-banding**: This is the most common technique used to stain chromosomes.It involves treating chromosomes with a chemical called Giemsa.(Dr. Marina Seabright 1971) **C-banding**: This technique is used to stain specific regions of the chromosomes called centromeres. (Pardue and Gall in 1968) **Q-banding**: This technique uses a quinacrine fluorescent dye to stain chromosomes(Torbjörn Caspersson Lore Zech, in 1968) - **Silent mutation**: The mutation does not change the amino acid sequence of the protein, and therefore has no effect on the organism. - **Missense mutation**: The mutation changes the amino acid sequence of the protein, potentially affecting its function. - **Nonsense mutation**: The mutation introduces a premature stop codon, resulting in a truncated protein that may not function properly. - **Frameshift mutation**: The mutation changes the reading frame of the genetic code, potentially leading to a completely different amino acid sequence. **Mainline Index** = (Sum of main line lengths / Palm length) × 100 1. **Hardy-Weinberg Equilibrium**: Godfrey Harold Hardy (1908) and Wilhelm Weinberg (1908) 2. **Inbreeding Coefficient**: Sewall Wright (1921) 3. **Genetic Drift**: Sewall Wright (1929) 4. **Genetic Distance**: Sewall Wright (1943) 5. **Genetic Polymorphism**: Ronald Fisher (1922) 6. **Balanced Polymorphism**: J.B.S. Haldane (1932) 7. **Transient Polymorphism**: Sewall Wright (1931) 8. **Genetic Load**: J.B.S. Haldane (1937) 9. **Genetic Isolate**: Luigi Luca Cavalli-Sforza (1966) 1. The population is large and randomly mating. 2. There is no mutation, gene flow, or genetic drift. 3. The alleles are selectively neutral. - p is the frequency of the dominant allele - q is the frequency of the recessive allele **Consanguineous Mating**: Individuals choose mates who are genetically related, such as cousins. 1. **Balanced Polymorphism**: The frequency of each allele is maintained at a stable level over time. 2. **Transient Polymorphism**: The frequency of each allele changes over time due to genetic drift or selection..**Paul Zamecnik and Mahlon Hoagland (1956) - discovered the role of transfer RNA in protein synthesis** - DNA (Deoxyribonucleic acid) is a double-stranded molecule that contains the genetic instructions for an organism. - RNA (Ribonucleic acid) is a single-stranded molecule that plays a crucial role in protein synthesis and other cellular processes. - The genetic code is the set of rules that dictates how the sequence of nucleotides in DNA is translated into the sequence of amino acids in proteins. - It\'s a triplet code, where each sequence of three nucleotides (codon) specifies one of the 20 amino acids or a stop signal. - Protein synthesis is the process by which cells create proteins from amino acids. - It involves transcription (creating a complementary RNA copy from DNA) and translation (building a polypeptide chain from the RNA sequence). - Protein structure refers to the 3D arrangement of amino acids in a polypeptide chain, which determines its function. - RFLPs (Restriction Fragment Length Polymorphisms): variations in the length of DNA fragments generated by restriction enzymes. - VNTRs (Variable Number Tandem Repeats): repeated sequences of DNA that vary in length between individuals. - STRs (Short Tandem Repeats): short repeated sequences of DNA that vary in length between individuals. - SNPs (Single Nucleotide Polymorphisms): single base pair variations in the DNA sequence. - Mitochondrial DNA is the genetic material found in mitochondria, the energy-producing structures within cells. - It\'s separate from nuclear DNA and has its own unique characteristics and inheritance patterns. - Genic mutations occur within a single gene and can affect its function. - Genomic mutations occur at the chromosomal level and can involve changes to the number or structure of chromosomes.