genetics
the branch of biology that studies heredity and variation in organisms
Heredity
the passing of characteristics from parents to offspring
Inheritance
it is the acquisition or reception of genetic quality's appearance to offspring. In sexual reproduction the genetic materials of two parents is combined and passed on to one individual.
Variation
Any difference between individuals of the same species. It is a state of having different traits and characteristics
Mandelian Genetics
It is one of the 3 branches of genetics. Also known as transmission genetics. It reviews the basic laws of inheritance that were described by Gregor Mendel.
Molecular genetics
One of the 3 brances of genetics. it deals with the chemical nature of the gene, the mechanisms of transmission, and its varied applications.
population genetics
One of the 3 branches of genetics. The behaivior of a particular gene on a group of organisms and how gene frequency is affected by environmental factors.
Genetic determines..
-Gender -Physical Characteristics -Potential diseases -Intelligence -Blood type -Amnormalities
Application of genetics
-Animals and plants improvement -Medicine -Genetic counseling -Legal application -Genetic Engineering -Genetic Test -Improve crop yields -Solve Agricultural problems
Gregor Johann Mendel
"Father of Genetics" An Augustinian monk discovered the basic principles of heredity through experiments in his monastery's garden. First scientist to give a satisfactory explanation of mechanisms of heredity.
Reason for using Pea (Pisum sativum)
Presence of observable traits with contrasting forms. Produces manu offspring in one cross. Short life cycle/short generation time. Ease in manipulating pollination. he crossed pollinated pea plants with opposite characteristics. tall with short, smooth with wrinkled, green seeds with yellow seeds etc.
Monohybrid Cross
A mating event between two parents that are heterozygous in respect to a single gene. This means that each parent carries two different alleles for the gene.
Phenotype
refers to the observable physical properties of an organism. This includes the organisim's appearance, development and behavior.
Genotype
An organism's complete set of heritable genes or genes that can be passed down from parents to offspring.
Allele
any alternative forms of genes in a genotype. It is represented by a letter
Dominant Trait
are inherited characteristics that appear in an offspring if it is contributed by a parent though dominant allele. it is represented by CAPITAL letter alleles
Recessive Traits
recessive traits are the weak, unexpressed trait of pair of alleles that has no effect in the phenotype of the heterozygous individual. It is represented by small letter alleles.
Homozygous traits
made up of two same alleles.
Heterozygous traits
made up of two different alleles
Punnett Square
Named from its inventor, Reginald Punnett. It is a diagram made of boxes used to predict the expected results of a genetic cross by considering all the possible combinations of gametes in a cross.
Rule of Unit Factors in Pair
Genetic characters are controlled by unit factors in pairs. In other words, genes are present in two associated copies in diploid organisms Example: DD plants have two alleles for tallness, dd plants have two alleles for dwarfism.
Principles of Dominance and Recessiveness
In the case of unlike unit factors, one can be dominant and the other can be recessive. In other words, when two different alleles of a gene are present, one may show its effect while the other may be masked. Example: Dd plants have a tall allele D and a dwarf allele d, but are phenotypically tall
Law of Segregation
During the formation of gametes, unit factors segregate randomly. ❑In other words, when sperm and eggs are formed, one of each allelic pair is randomly distributed to each gamete. Example: a Dd plant makes pollen or eggs, each randomly receives either the D allele or the d allele.
law of independent assortment
the alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.
Chromosomes
It is where genetic material or the gene is located which in turn is found in the nucleus. These are coiled DNA and associated with proteins called histones.
P arm
the label for the short arm of the chromosome
q arm
the label for the long arm of the chromosome
centromere
this is the chromosomes construction point, whoch divide the chromosomes into sister chromatids, or arms
sister chromatid
it is called that way because they consider reproduction as a female trait.
Metacentric
is a chromosome whose centromere is centrally located.
Submetacentric
a chromosome whose centromere is located near the middle.
Acrocentric
A chromosome where the centromere is not central and is instead located near the end of the chromosome
telocentric
is a chromosome whose centromere is located at one end.
Spermatogenesis
sperm cell production. the origin and development of the sperm cells within the male reproductive organs, the testes.
❑Produces 2 types of spermatozoa or sperm cells
❑X- bearing and Y-bearing cells
❑ “heterogametic”
Oogenesis
egg cell production. the process of formation of female gametes.
❑ Produces only 1 type of ovum or egg cell
❑ - X-bearing cell
❑ - “Homogametic”
formation of gametes
Where the genetic history of an individual starts
Sex cells
will undergo meiosis to produce cells with a haploid (n) number of chromosomes.
Fertilization
sperm cell (n) and egg cell (n) unites to restore the number of chromosomes (n + n = 2n).
Haploid
refers to the presence of a single set of chromosomes in an organisms cell.
Diploid
refers to the presence of two complete sets of chromosomes in an organism cell with each parent contributing a chromosomes to each cell.
Traits
Specific characteristics of an individuals. Can be determined by genes, environmental factors, or by a combination of both.
Autosomes
A type of chromosome. controls the inheritance of all the characteristics
44 chromosomes (22 pairs)
Sex chromosome
A type of chromosome. It determines the sex of the individual
2 chromosomes (last pair)
Variation
Term used to describe the variation in the DNA sequence.
Traits controlled by a single gene
Eye color Freckles Attached earlobes Ability to roll your tongue
Trait determined by multiple allese
ABO blood type groups Physical structures
Polygenic trait
A characteristics, such as height or skin color that is influenced by two or more genes, EXAMPLES: height, weight, hair
sex-linked or X-linked genes
The genes on the X chromosomes These are inherited through the X chromosomes.
y linked or holandric genes
The genes on the Y chromosomes. These are inherited through the Y chromosomes.
sex influence genes
Are autosomal genes whose expression is affected by the sex of the individual. occurs when phenotypes are different between males and females with the same genotype.
Sex limited Genes
Are autosomal genes whose expression is manifested in one sex only because of the sex hormones. These traits can only be expressed in one sex or the other the traits are not found on the X and Y chromosomes meaning they are generally autosomal.
pedigree
A chart that shows the family history. It also illustrates how a trait is inherited over several generations in our family.
carrier
Individuals who are heterozygous for the inherited trait but do not express it. They can pass the allele of the trait to their children.
genetically modified organisms (GMO)
GMO is a plant, animal, microorganism, or other organisms whose genetic makeup has been modified in a laboratory using genetic engineering or transgenic technology.
GMO in plants
To produce a GM plant, new DNA is transferred into plant cells. Usually, the cells are then grown in tissue culture where they develop into plants. The seeds produced by these plants will inherit the new DNA.
GM plant Benefits
-increased crop yields -reduced need for pesticides -reduced costs for food or drug production -greater food security, and medical benefits -enhanced nutrient composition and food quality
GMO's in animals
Genetic modification of an animal involves altering its genetic material by adding, changing, or removing certain DNA sequences in a way that does not occur naturally. ❑It aims to modify specific characteristics of an animal or introduce a new trait, such as disease resistance or enhanced growth. example: Toxic to insects but not harmful to mammals. GM use - To kill insects on GM cotton crops Golden orb Weaver Gene is switched on in mammary glands of GM goats to mass-produce the silk fiber for artificial tendons and ligaments and for bullet-proof vests and parachutes.