Post by Kickingbird on Mar 26, 2004 19:18:02 GMT -5
Fundamental Genetics Definitions
Allele – Form of a gene at a locus; members of a pair or series of different hereditary factors that may occupy a given locus on a specific chromosome and that segregate in formation of gametes
Amino Acids – Building blocks of proteins
Animal Breeding – Application of Mendelian, population, quantitative and molecular genetics principles for the improvement of animal populations
Autosomes – All chromosomes except sex chromosomes
Centromere – Spindle-fiber attachment region of chromosome (compare acrocentric, sub-metacentric and metacentric)
Chromosomes – Nucleoprotein molecules that are microscopically visible during cell division; Carry genes arranged in linear order
DNA – Deoxyribonucleic acid; Genetic material; Linear molecule usually double-stranded and helically coiled, strands bonded by pairs of nitrogenous bases (Cytosine pairs with Guanine; Adenine pairs with Thymine)
Diploid – An organism or cell with 2 sets of chromosomes (2n)
Dominant – Alleles that have an observable effect when present in only one member of a chromosome pair
Exon – Coding or expressed sequences of genes; transcribed into mRNA and translated into protein
F1 – First filial generation or first-cross population; offspring obtained from mating of two parental populations
F2 – Second filial generation or second-cross population; offspring obtained from inter se mating of F1 individuals
Gamete – Germ cell; sperm or ovum; contain haploid number of chromosomes
Gene – Unit of inheritance; Specific sequence of DNA with defined beginning and end
Gene Frequency – Proportion, in a population, of the loci of a give allelic series occupied by a particular allele
Genetic Code – Rules by which the amino acid sequence of a polypeptide chain is specified by the order of bases in DNA, in which groups of three bases (codons or triplets) specify one of the 20 amino acids of which proteins are composed
Genetics – The science of heredity and variation
Genome – Complete set of chromosomes (n) inherited from one parent
Genotype – Complete genetic make-up of an individual
Haploid – An organism or cell with only one set of chromosomes (n)
Heterozygous – A given locus in a chromosome pair carries unlike members of a pair or series of alleles
Homologous Chromosomes – Pairs of chromosomes where 1 chromosome is from each parent
Homozygous – Both members of chromosome pair carry same gene at a specific locus
Ideogram – drawing of a karyotype depicting specific banding patterns of each chromosome
Intron – Intervening DNA sequences that separate exons of genes
Karyotype – Microscopic picture of the chromosomes of an individual; Chromosomes arranged in order of length and according to position of centromere
Locus – Region (location) on chromosome where specific gene pair or allelic series is located
Meiosis – Process where chromosome number of reproductive cells is reduced to the haploid number; results in the formation of gametes
Mendel’s First Law – The Law of Segregation and Recombination; Individual genes are present in duplicate, separate (segregate) in the formation of gametes and recombine as discrete units during fertilization (i.e., individual genes maintain their identity without blending with other genes in the zygote)
Mendel’s Second Law – The Law of Independent Assortment; “The relation of each pair of different characters in a hybrid union is independent” (i.e., one member of a pair of genes going to one germ cell has no influence on which member of any other pair of genes goes to that cell)
Metaphase Spread – Chromosomes isolated at metaphase stage of the cell cycle and stained for viewing under a microscope
Mitosis – Chromosome duplication followed by migration of chromosomes to the ends of the spindle and division of cytoplasm
Phenotype – External appearance or some other observable or measurable characteristic of an individual
PCR – Polymerase chain reaction; Method for amplifying DNA
Polymorphism – DNA sequence variation at a particular locus that is maintained in the population as different alleles
Probability – Mathematical expression relating to frequencies with which specific events may occur or fail to occur; ratio of specified outcome to total possible outcomes
Recessive – Alleles that have no observable effect unless present in both members of a chromosome pair
RNA – Ribonucleic acid; Nucleic acid comprised of the nitrogenous bases Adenine, Cytosine, Guanine and Uracil; Three types of RNA include messenger RNA (mRNA, type of RNA that is translated into protein), ribosomal RNA (rRNA) and transfer RNA (tRNA)
Sex Chromosomes – Chromosomes related to determination of sex; unequal chromosome pair in male mammals and female birds
Transcription – Synthesis of mRNA from a DNA template
Translation – Synthesis of protein from an mRNA template
Zygote – Fertilized ovum (egg); Diploid cell formed from the union of two gametes (reproductive cells)
Allele – Form of a gene at a locus; members of a pair or series of different hereditary factors that may occupy a given locus on a specific chromosome and that segregate in formation of gametes
Amino Acids – Building blocks of proteins
Animal Breeding – Application of Mendelian, population, quantitative and molecular genetics principles for the improvement of animal populations
Autosomes – All chromosomes except sex chromosomes
Centromere – Spindle-fiber attachment region of chromosome (compare acrocentric, sub-metacentric and metacentric)
Chromosomes – Nucleoprotein molecules that are microscopically visible during cell division; Carry genes arranged in linear order
DNA – Deoxyribonucleic acid; Genetic material; Linear molecule usually double-stranded and helically coiled, strands bonded by pairs of nitrogenous bases (Cytosine pairs with Guanine; Adenine pairs with Thymine)
Diploid – An organism or cell with 2 sets of chromosomes (2n)
Dominant – Alleles that have an observable effect when present in only one member of a chromosome pair
Exon – Coding or expressed sequences of genes; transcribed into mRNA and translated into protein
F1 – First filial generation or first-cross population; offspring obtained from mating of two parental populations
F2 – Second filial generation or second-cross population; offspring obtained from inter se mating of F1 individuals
Gamete – Germ cell; sperm or ovum; contain haploid number of chromosomes
Gene – Unit of inheritance; Specific sequence of DNA with defined beginning and end
Gene Frequency – Proportion, in a population, of the loci of a give allelic series occupied by a particular allele
Genetic Code – Rules by which the amino acid sequence of a polypeptide chain is specified by the order of bases in DNA, in which groups of three bases (codons or triplets) specify one of the 20 amino acids of which proteins are composed
Genetics – The science of heredity and variation
Genome – Complete set of chromosomes (n) inherited from one parent
Genotype – Complete genetic make-up of an individual
Haploid – An organism or cell with only one set of chromosomes (n)
Heterozygous – A given locus in a chromosome pair carries unlike members of a pair or series of alleles
Homologous Chromosomes – Pairs of chromosomes where 1 chromosome is from each parent
Homozygous – Both members of chromosome pair carry same gene at a specific locus
Ideogram – drawing of a karyotype depicting specific banding patterns of each chromosome
Intron – Intervening DNA sequences that separate exons of genes
Karyotype – Microscopic picture of the chromosomes of an individual; Chromosomes arranged in order of length and according to position of centromere
Locus – Region (location) on chromosome where specific gene pair or allelic series is located
Meiosis – Process where chromosome number of reproductive cells is reduced to the haploid number; results in the formation of gametes
Mendel’s First Law – The Law of Segregation and Recombination; Individual genes are present in duplicate, separate (segregate) in the formation of gametes and recombine as discrete units during fertilization (i.e., individual genes maintain their identity without blending with other genes in the zygote)
Mendel’s Second Law – The Law of Independent Assortment; “The relation of each pair of different characters in a hybrid union is independent” (i.e., one member of a pair of genes going to one germ cell has no influence on which member of any other pair of genes goes to that cell)
Metaphase Spread – Chromosomes isolated at metaphase stage of the cell cycle and stained for viewing under a microscope
Mitosis – Chromosome duplication followed by migration of chromosomes to the ends of the spindle and division of cytoplasm
Phenotype – External appearance or some other observable or measurable characteristic of an individual
PCR – Polymerase chain reaction; Method for amplifying DNA
Polymorphism – DNA sequence variation at a particular locus that is maintained in the population as different alleles
Probability – Mathematical expression relating to frequencies with which specific events may occur or fail to occur; ratio of specified outcome to total possible outcomes
Recessive – Alleles that have no observable effect unless present in both members of a chromosome pair
RNA – Ribonucleic acid; Nucleic acid comprised of the nitrogenous bases Adenine, Cytosine, Guanine and Uracil; Three types of RNA include messenger RNA (mRNA, type of RNA that is translated into protein), ribosomal RNA (rRNA) and transfer RNA (tRNA)
Sex Chromosomes – Chromosomes related to determination of sex; unequal chromosome pair in male mammals and female birds
Transcription – Synthesis of mRNA from a DNA template
Translation – Synthesis of protein from an mRNA template
Zygote – Fertilized ovum (egg); Diploid cell formed from the union of two gametes (reproductive cells)