Chapter 11 - How Genes are Controlled Flashcards
What are alleles?
alternate forms of a gene (ex. blue and brown eyes), represented by letters or symbols
What does homozygous mean?
individual with identical alleles (ex. GG or gg)
What does heterozygous mean?
individual with two different alleles (ex. Gg)
What is a genotype?
the genetic content of an individual
What is a phenotype?
the external appearance of an individual (“function”)
What does dominant mean?
allele represented by uppercase letter, the dominant trait is visible in heterozygous individuals
What does recessive mean?
allele represented by the lowercase letter. The recessive trait is not visible in heterozygous individuals. Two recessive traits must be present to express that trait
What are units of inheritance?
genes
How is DNA inherited in sexual reproduction?
two haploid gametes fuse to form one diploid zygote
sexual reproduction = meiosis –> gametes (sex cells) –> fertilization
What is meiosis?
cell division for making gametes (DNA duplication, division I, division II)
What is a locus?
a specific location of a gene along the chromosome
What are wild-type traits?
traits seen most often in nature
-not necessarily dominant
What is a pedigree?
family genetic tree
-shows the history of a trait in a family and allows geneticists to analyze human traits.
What is incomplete dominance?
when the appearance of F1 hybrids fall between the phenotypes of the two parents (red + white = pink)
What is codominance?
both alleles are expressed in heterozygous individuals (AB blood)
