Chapter 6 : Transmission Genetics And The Sources Of Genetic Variation Flashcards
Alleles
Different variants of the same gene
Amino acids
Chromatin
DNA wound around proteins called histones
Chromosomal deletion
Entails the loss of a large section of a chromosome
Chromosomal duplication
Occurs when a section of a chromosome is duplicated
Cis regulatory elements
Affect genes at nearby sites on the same chromosome
Codons
Three-base Sequences
Crossing-over
The physical exchange of segments of DNA on homologous chromosomes
Distribution of fitness effects
Dominant
Epigenetic inheritance
Heritable across mitosis from one cell generation to the next or even across meiosis from one organismal generation to the next
Exons
Stretches of DNA that code for protein products
Frame shift mutation
When an insertion or deletion does not occur in a multiple of three nucleotides
Gametes
Sex cells
Gene
Sequences of DNA that code for functional products
Genetic code
Genotype
Heterozygotes
Diploid individual with two different alleles at a locus are referred
Histones
Homozygotes
Diploid Individuals with copies of the same allele at a locus
Incomplete dominance
Can arise with heterozygote generates an intermediate phenotype
Introns
Stretches of DNA that do not normally encode proteins
Inversion
Involves a 180° flip in a section of a chromosome
Law of independent assortment
States that which allele is passed down to the next generation at one locus, is independent of which allele is passed down to the next generation at another locus
Law of segregation
States that each individual has two gene copies at each locus and that these gene copies segregate during gamete production, so that only one gene copy goes into each gamete
Locus
Location of gene copies in the genome
Meiosis
Process that begins with a single diploid cell. One round of DNA
Nonsense mutation
When a base substitution creates a stop codon where there was not one previously
Nonsynonymous mutation
When a base change specifies the production of a different amino acid
Promoter
A short DNA sequence before the transcribed part of the gene
Recessive
Regulatory elements
Stretches of DNA that influence the rate at which RNA molecules are transcribed from DNA
Synonymous mutation
When a base change does not alter the amino acid that a codon specifies, silent mutation
Trans regulatory elements
Modify the expression or activity of genes on a different chromosome
Transcription
Process where a complementary and antiparallel strand of RNA is synthesized from a strand of DNA
Transition
When a purine is replaced by a purine or when a pyridine is replaced by a pyridine
Translation
Translocation
Mutation in which a section of one chromosome moves to another chromosome
Transmission Genetics
Mechanisms by which genes are passed from parents to offspring
Transversion
When a purine replaces a pyrimidine or when a pyrimidine replaces a purine
How did the discovery of particulate inheritance resolve a serious concern about Darwin’s theory?
Why is the genetic code said to be degenerate?
How does an understanding of DNA, amino acids, and proteins help us understand the evolution of life?
What is transmission genetics, and how does our understanding of this topic affect the way that we study the process of evolution?
How does mutation generate genetic variation, and how do mutations affect the evolutionary process?
What is blending and how does it affect variation?
Blending is a disproven idea that genes “blend” together. If it were true, then variation would be lost/consumed.
What are the four nitrogenous bases that are in DNA?
What does ribosomal RNA do?
What does transfer RNA do?
Enhancers
Regulatory elements that increase the rate of transcription
Silencers
Regulatory elements that decrease the rate of transcription
What cellular processes cause segregation and independent assortment of alleles?
Meiosis
What would cause an exception to segregation and independent assortment of alleles?
Whether the loci is linked
What are the sources of genetic variation?
Sex, migration, mutation
Fusion
Chromosomes fuse
Fission
Chromosomes break apart
Point mutation
Single nucleotide substitution or change
Polyploidy
More than 2 copies of all chromosomes; common in plants
Insertion
New base pairs included into DNA strand
Deletion
Base pairs are deleted
