Genbio genetics

diploid

• is a result of the union of a haploid egg cell and a haploid sperm cell

science of genetics

• studies how these characteristics are inherited

• also addresses how other differences or variations occur in offsprings as a result of environmental and other nongenetic factors

chromosomes

• are made up of DNA molecules coiled around histones

• the sequence of DNA bases in a ______ will determine the codes for proteins responsible for the observable characteristics of an individual

genome

• set of all genes found in a cell responsible for the characteristics of an individual

• composed of two sets of chromosome, paternal and maternal sets

homologous chromosomes

• refer to a pair of of paternal and maternal chromosomes that are of the same size, similar gene locations (loci), common banding pattern and same centromere location

alleles

• one of two or more alternative forms of genes

genotype

• refers to the totality of the genetic makeup of an individual

• may also specifically refer to the combination of the alleles found in a homologous chromosome

• are represented by symbols

phenotype

• refers to the observable expression of a particular genotype

homozygous

• when two similar alleles are present in a pair, the genotype is called ______

heterozygous

• when two different alleles are paired, the genotype is called ______

dominant allele

• allele that is expressed in a heterozygous condition is called _____

recessive allele

• allele that is not expressed in a heterozygous condition is called _____

law of segregation

• during the formation of gametes, the paired unit factors segregate randomly so that each gamete receives one or the other with equal likelihood

principle of dominance and recessiveness

• when two unlike factors responsible for a single trait are present in an individual, one unit factor is dominant over the other, which is said to be recessive

unit factors in pairs

• the genetic characters are controlled by unit factors that exist in pairs in individual organisms

law of independent assortment

• during gamete formation, segregating pairs of unit factors are assorted independently of eachother

• The inheritance of one trait is not affected by the inheritance of another trait

gregor johann mendel

• father of Genetics

• an Augustinian monk who discovered the basic principles of heredity through experiments in his garden.

• his observations became the foundation of modern genetics and the study of heredity, and he is widely considered a pioneer in the field of genetics.

parental generation

• a cross of purebred (homozygous) parents.

first filial generation

• F1

• the product of the Parental Generation

second filial generation

• F2

• the product of the self-fertilization of the products of F1 generation

codominance

• When two dominant alleles are present, both alleles will be expressed. There is the absence of a recessive allele

• As a result, a third phenotype is produced in a heterozygous condition

• The third phenotype is not a blending of the parental traits; rather, both parental traits are displayed.

incomplete dominance

• When dominant alleles are absent, only a recessive allele will combine with another recessive allele.\

• The offspring does not resemble either of the parents

multiple alleles

• More than two alleles exist in a certain character

agglutinogens

• also called A and B antigens

• the presence of this causes the formation of agglutinin

agglutinin

• substance that makes particles coagulate

• presence of agglutinogens causes the formation of this

rhesus factor

• is an inherited protein found on the surface of red blood cells

• no Rh = negative

• yes Rh = positive

lethal genes

• A condition when a certain combination of alleles will result to death of the carrier

polygenic inheritance

• Traits that are controlled by two or more genes.

polygenes

• genes involved in polygenic inheritance. Often found in different chromosomes

sex-linked inheritance

• inheritance of genes located in the sex chromosomes

• expression of this genes is affected by the sex of the individual

sex- influenced inheritance

• Refers to autosomal traits whose expression of dominance is affected by the gender of the individual

• Follows the Mendelian pattern of dominance and recessiveness. However, the effect in one gender is dominant whereas it is recessive in another gender

pleiotropy

• A condition when one gene causes several effects (multiple traits) in various organs of the body

• genes with ______ effects end to be more severe and may affect multiple systems.

gene

• describes the specific sequence of DNA containing the information codes for protein

monohybrid cross

•  Cross involving a single trait/one trait inheritance

dihybrid cross

• Cross involving 2 traits