Chapter 14-Non Mendelian Genetics Flashcards
What is sex linked inheritance?
sex chromosomes segregate in males to form X/Y bearing gametes
Genetic recombination results from ________________.
crossing over
What determines the frequency of crossing over?
distance between genes
crossing over is rare when to genes are…
close together
What is a genetic map?
diagram showing the relative positions of genes along a chromosome
What are the exceptions to Mendelian genetics?
- multiple alleles
- codominance
- incomplete dominance
- pleiotropy
- gene interaction
- epistasis
- quantitative traits
What is multiple allelism?
more than 2 alleles code for one gene
What is codominance?
simultaneous full expression of the phenotype of both alleles of a heterozygote
What is incomplete dominance?
heterozygotes have a phenotype that is an intermediate of the phenotypes of two different homozygotes
What is pleiotropy?
one gene influences multiple traits (ex: cystic fibrosis, sickle-cell anemia, marfan syndrome)
What is gene interaction?
multiple genes work together to produce a single phenotype
How do you recognize gene interaction?
intermediate phenotype in F1, and new phenotype in F2
What is epistasis?
one gene alters the expression of another gene (ex: baldness)
- can either mask or enhance a trait
What are quantitative traits?
- traits that vary continuously over a large range
- controlled by multiple genes
- influenced by the environment (ex: weight, height, IQ)
Mendel’s law of segregation reflects what event in meiosis?
separation of homologous chromosomes at meiosis 1
