Download Introduction to Genetics Study Guide

Introduction to Genetics Study Guide
Vocabulary
Genetics scientific study of heredity
True-breeding describes organisms that if allowed to self-pollinate, they would produce
offspring identical to themselves
Trait a distinguishing characteristic that can be inherited and varies from one individual
to another
Hybrid offspring of crosses between parents with different traits (heterozygous)
Gene chemical factors that determines traits
Allele different forms of a gene
Segregation separation
Gamete sex cell
Principle of probability can be used to predict the offspring outcomes of genetic crosses
Principle of dominance some alleles are dominant and some are recessive. Dominant
alleles will mask recessive alleles
Principle of segregation separation of alleles during gamete formation; organisms inherit
two copies of each gene and donate one copy to each of their offspring
Principle of independent assortment independent segregation of genes during the
formation of gametes. Explains genetic variation within species
Punnett square diagram used to determine gene combinations of a genetic cross
Homozygous organisms that have to identical alleles for the same trait
Heterozygous organisms that have different alleles for the same trait
Phenotype physical characteristics; affected by genotype and environment
Genotype genetic makeup
Homologous chromosomes refers to chromosomes that each have a corresponding
chromosome that you inherit from your parents
Incomplete dominance situation in which one allele is not completely dominant over
another and making a 3rd phenotype
Codominance situation in which both alleles of a gene contribute to the phenotype of the
organisms, neither is dominant over the other and therefore both alleles show in the
phenotype
Multiple alleles three or more alleles of the same gene; unlike the traits studied by
Mendel, most traits are produced by genes that are multiple
Polygenic trait trait controlled by two or more genes; height is an example
Epistatic gene that overshadows all other genes for a particular trait (ex-albinism)
Diploid cell that contains both sets of homologous chromosomes (two sets) represented
by 2N
Haploid cell that contains only a single set of gene (one set) represented by N
Meiosis process of reduction division in which the number of chromosomes per cell is cut
in half through the separation of homologous chromosomes in a diploid cell
Crossing over exchange in alleles between homologous chromosomes to produce new
combinations of alleles. Increases variety among sexually reproducing organisms
The work of Gregor Mendel considered the father of genetics by controlling the
fertilization process with pea plants to study the inheritance of traits. Principles apply to
all organisms.
Punnett Squares can be used to predict and compare the genetic variations that will result
from a cross
know how to read/cross know the results of parent generation cross (purebred), F1
generation (hybrids) cross and F2 generation cross
what they stand for used to predict possible outcomes for offspring
results heterozygous/hybrid & homozygous/purebred results of all types of
crosses. Phenotypic and genotypic ratios. (P generation; F1 generation; F2 generation)
monohybrid examines the inheritance of on specific trait
dihybrid examines the inheritance of two traits (two hybrids will produce a
9:3:3:1 phenotypic ratio). Four different allele combinations
Genetics and the environment DNA is the blueprint but characteristics can be determined
by interactions between genes and the environment
Blood Type
Dominant vs recessive A and B are dominant and O is recessive
Universal donor (o) vs universal receiver (AB)
Meiosis results in 4 genetically different haploid cells or gamete cells
Compare and contrast mitosis and meiosis mitosis makes genetically identical
cells, makes diploid cells, takes place throughout organism’s lifetime, involved in asexual
reproduction. Meiosis makes genetically unique cells, makes haploid cells, takes place
during certain times in life cycle, involved in sexual reproduction
Phases prophase I, metaphase I, anaphase I, telophase I, prophase II, metaphase II,
anaphase II, telophase II (remember to review what each phase does)
gamete #/symbol sex cell with half the number of body cell (somatic cell)
represented by N