Genetics Flashcards
Genetics as a science.
Genetics as a science of two fundamental interconnected properties of living organisms
Heredity & Variability
Main goals of genetics.
- Study of material basis of heredity.
- Study of the flow of genetic information in cell.
- Study of the patterns of genetic determination.
- Study of patterns of variability.
Genetic methods
Hybridological
Genealogical
Cytogenetic
Biochemical
Mathematical
Molecular
Historical genetic periods
1990-1910 : propose chromosomal theory of heredity.
1910-1920 : Morgan and his colleagues confirmed the chromosomal theory.
1920-1940 : - Mulier show’s x.rays induce mutation.
- Griffith’s transformation experiments of transform non-pathogenic bacterial strains to pathogenic.
1940-1953 : Griffith’s discovers that A=T , C= G in DNA molecule.
1953- 2013 : propose double helix structure of DNA , existence of mRNA.
Heredity, Variability & Inheritance
Heredity:it is a propertie of living organisms to transferring biological informations to the next generation.
Variability: it is a propertie of living organisms to change heredity traits or appearance in ontogenisis.
Inheritance: it’s a process of transferring genetic information from generation to another one.
Types of inheritance
Single
Multiple
Multi-path
Hierarchical
Hybrid
Mendel experiments with pea plant
Working with pea garden . Mendel found that crosses between parents that different in one trait produce F1 offspring that all expressed the traits of one parent.
Observable traits are referred to as dominant and non-expressed traits are recessive.
Monohybrid cross & principle of uniformity.
- Monohybrid cross : is study of inheritance of one characteristic in the genetic diagrams for these crosses.
- Mendel’s first law the principle of uniformity . It’s says that differ in just one trait are crosses than the resulting hybrids will be unformain the chosen trait.
Principle of Segregation
Mendel’s second law is principle of Segregation . It states that individuals of the F2 generation aren’t uniform but that traits segregate.
Dominance & recessivenss
Dominance: it’s a great influence by one of allele that affect in the same in the same inherited character.
recessivenss: it’s a minor influence or the failure of one allelis in individual to Express itself.
Dihybrid & polyhybrid
Dihybrid cross : A cross between two organism differing by two pairs of Alternative character.
Polyhybrid: A hybrid whose parents differ in characters. an individual or group heterozygous for more than one pair of genes.
Principles of independent assortment.
Mendel’s third law it’s says that is inherited independently by others and it’s covers the case that new combinations of genes can arise which were not existing before.
Test cross definition.
Test cross is the cross between individuals organisms of dominant phenotype.
Main terms of genetics: ( gene , allelic - non-allelic - Genotype - Phenotype - Homozygous.)
Gene : is a set of molecule of DNA encoding the information about primary structure of polypeptide or nucleotide of tRNA and rRNA molecules.
Allelic genes : genes are located on same areas in homologous chromosomes (ex. Alleles are responsible of color in pea seeds yellow and green. Aa )
Non-allelic genes : genes are located in different areas of chromosome ( alleles responsible for shape of pea AABB.)
Genotype: it’s a set of all genes of an organisms and genetic meackup of an organisms.
Phenotype : a set of genes characteristic of an individual of resulting of interaction genotype with environment.
Homozygous body: it’s the body have two identical alleles of gene and producing a single type of gametes.
Cytoplasmic inheritance
Inheritance of characters controlled by Genes present in cell cytoplasm. Rather than genes chromosomes in cell neculas ex. Cytoplasmic inheritance controlled by mitochondrial Genes.
