Chapter 11, 12.1-12.2 Flashcards
What is a character?
A heritable feature that varies among individuals
What is a trait?
Each variant for a character
What does it mean to be true breeding?
Organisms that, over many generations, have produced the same genetic variety over and over
What is hybridization?
The crossing of 2 true-breeding varieties
What is a P generation? the F1 generation?
The generation true breeding parents, their offspring are the F1 generation
What are alleles and what are they responsible for?
Alleles are alternative versions of the same gene. The are responsible for variations in inherited characters
What is a gene?
A sequence of nucleotides at a specific location along a particular chromosome
What is the law of segregation?
A law that states that two alleles for a heritable character segregate during gamete formation and end up in different gametes
What is the difference between phenotype and genotype?
Phenotype: physical or physiological makeup
Genotype: Genetic makeup
What is a testcross?
A test devised by mendel where you cross either a homozygous dominant or hererozygous genotype(you’re trying to determine which one) with a homozygous recessive and the outcome will give you the genotype of first plant
What are monohybrids and what is a monohybrid cross?
A monohybrid is something that is heterozygous for one particular trait and a monohybrid cross is a cross between such heterozygotes
What is a dihybrid and a dihybrid cross?
Individuals that are heterozygous for 2 characteristics, a dihydrid cross is a cross between two dihybrids. Example is crossing YYRR and yyrr to get YyRr, YyRr is the dihybrid
What is the law of independent assortment?
A law that states that two or more genes assort independently-each pair of alleles segregates independently of each other pair during gamete formation. APPLIES ONLY WHEN GENES ARE ON DIFFERENT CHROMOSOMES OR VERY FAR APART ON THE SAME CHROMOSOME
What is incomplete dominance?
A situation where neither allele is completely dominant, and the offspring lie somewhere in between the two parental varieties
What is codominance?
Each allele effects the offsprings phenotype in separate and distinguishable ways
What is pleiotropy?
A property that most alleles have where they have multiple phenotypic effects
What is epistasis?
The phenotypic expression of a gene at one locus alters that of a gene in a second locus
What are quantitative characters?
Those that vary in the population along a continuum(example: skin color, height)
What is polygenic inheritance?
The additive effect of 2 or more genes on a single phenotype
What does it mean if a gene is multifactorial?
Many factors, both genetic and environmental, collectively influence the phenotype
When is phenotypic range usually broadest?
When the characters are polygenic
What is the chromosome theory if inheritance?
The theory that Mendelian genes have specific loci along chromosomes, and it is the chromosomes that undergo segregation and independent assortment
What accounts for the independent assortment of alleles for two or more genes located on different chromosomes?
The behavior of non-homologous chromosomes
What is a wild type?
The phenotype for a character most commonly observed in a natural population
What are Mendel’s two laws of inheritance?
The law of independent assortment and the law of segregation
