Genes PDF

Genes The Collaborative Gene: ​ Human life begins as a single cell ​ The nucleus of each cell contains chromosomes ​ Units of hereditary information composed of DNA ​ Help cells to reproduce themselves ​ Manufacture the proteins that maintain life Mitosis and Meiosis: ​ All human body c...

Genes The Collaborative Gene: ​ Human life begins as a single cell ​ The nucleus of each cell contains chromosomes ​ Units of hereditary information composed of DNA ​ Help cells to reproduce themselves ​ Manufacture the proteins that maintain life Mitosis and Meiosis: ​ All human body cells have a nucleus with chromosomes (except red blood cells and some hair/nail cells) ○​ 23 pairs/46 chromosomes ​ Mitosis ○​ Body cells duplicate themselves to grow/repair tissues through mitosis (make exact replicas or daughter cells) ○​ All body cells reproduce this way except neurons ○​ Throughout this copying process, mistakes can be made (cancer, cell death, etc) ​ Meiosis ○​ Human sex cells (gametes) are formed through cellular division or meiosis ○​ The haploid cells created have unique combinations of chromosomes and genes (not duplicates of mom/dad) ○​ Has only ½ the number of chromosomes How are Genes Inherited: ​ The diversity of new life ​ When new life is formed, the 23 chromosomes from the ovum match up with 23 chromosomes from the sperm cell ​ This creates a new human cell with 46 chromosomes in 23 pairs, known as a zygote ​ The chromosomes in one zygote could be combined in one of more than 8 million possible combinations Understanding the Genome:  ​ Alleles are different forms of genes that can affect individual characteristics and disease risk (sickle-cell; genetic mutation of HBB) Mendelian Genetics: ​ Dominant vs recessive genes ​ 2 alleles for a trait ​ “Y” represents dominant traits and “y” represents recessive traits ​ The only way for a recessive gene to be displayed is if it is homozygous (yy) Single-Gene Inheritance Patterns: ​ Single-gene disorders are linked to a single gene ○​ May be possible to predict and prevent disease transmission if the gene is known ​ Recessive inheritance pattern ○​ Two copies of disease carrying allele ○​ Sickle-cell disease; genetic carrier ○​ Thalassemia ○​ Cystic fibrosis ○​ Tay Sachs disease ​ Dominant inheritance pattern ○​ One copy of disease carrying allele ○​ Huntington disease ○​ Marfan syndrome ​ Sex-linked genes ○​ When a mutated gene is carried on the X chromosome, the result is called X-linked inheritance  ○​ Most X-linked inherited diseases manifest in males who have only one X chromosome ​ Hemophilia, color blindness, muscular dystrophy ​ Some disorders happen during meiosis Gene Linked Abnormalities: What Role do Proteins Play? ​ Required for structure, function, and regulation of body tissues/organs ​ Made of amino acids The Epigenome: ​ The genome area devoted to gene regulation (turns genes on and off) ​ Controls which genes are expressed by changing chemicals around the DNA double helix (epigenetic marks) ​ Changes with age and follows an epigenetic clock ​ Can be transmitted to future generations through alterations in meiosis ​ Provides a research base related to understanding and treatment of environmental triggers for many disorders Heredity-Environment Correlation: ​ Passive ○​ Genetically linked biological parents provide rearing environment for children based on their own genes/behavior ○​ Ex: musical parents will usually have musical children and are likely to provide an environment rich in music for their children ​ Evocative  ○​ Your genes impact how you interact with environment and elicits certain types of environments ○​ Ex: a happy and outgoing child elicits smiles from strangers ​ Active ○​ Also called niche-picking, children seek environments that they find compatible and stimulating and suited for their genetically influenced abilities ○​ Ex: libraries, sports fields, and musical environments are examples of niches children may seek