AP bio: heriditary Flashcards
mendelian genetics
traits that illustrate the laws of inheritance first described in the 1860s by Gregor Mendel, known as the father of genetics.
Gregor Mendel
father of genetics and PEA PLANT GUY
Segregation
allele pairs separate randomly from each other during the production of gametes: egg and sperm. Because allele pairs separate during gamete production, a sperm or egg carries only one allele for each inherited trait.
genes
a discrete unit of heredity information consisting of a specific nucleotide sequence in DNA
independent assortment
formation of random combinations of chromosomes in meiosis and of genes on different pairs of homologous chromosomes by the passage according to the laws of probability of one of each diploid pair of homologous chromosomes into each gamete independently of each other pair.
P generation
formation of random combinations of chromosomes in meiosis and of genes on different pairs of homologous chromosomes by the passage according to the laws of probability of one of each diploid pair of homologous chromosomes into each gamete independently of each other pair.
F1 generation
the first filial, hybrid (heterozygous) offspring arising from a parental cross
F2 generation
the offspring resulting from interbreeding (or self-pollination) of the hybrid F1 generation
punnett square
a diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotype
law of segregation
states that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation
law of independent assortment
sates that each pair of alleles segregates, or assorts, independently of each other pair during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes
heterozygous
having two different alleles for a given gene
homozygous
having two identical alleles for a given gene
recessive
an allele whose phenotypic effect is not observed in a heterozygote
allele
any of the alternative versions of a gene that may produce distinguishable phenotypic effects
chromosome
a cellular structure carrying genetic material, found in the nucleus of eukaryotic cells
genotype
the genetic makeup, or set of alleles, of an organism
phenotype
the observable physical and physiological traits of an organism, which are determined by its genetic makeup
pedigree
a diagram of a family tree with conventional symbols, showing the occurrence of heritable characters in parents and offspring over multiple generations
dihybrid
an organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles
AABB x aabb= AaBb
monohybrid
an organism that is heterozygous with respect to a single gene of interest. AA x aa= Aa
hybrid
offspring that results from the mating of individuals from two different species or from two true-breeding varieties of the same species
polygenic
an additive effect of two or more genes on a single phenotypic character
pleiotropy
the ability of a single gene to have multiple effects
somatic cell
any cell in a multicellular organism except a sperm or egg or their precursors
gamete
a haploid reproductive cell, such as an egg or sperm. unite during sexual reproduction to produce a diploid zygote
polyploidy
a chromosomal alteration in which the organism possesses more than two complete chromosome sets. it is the result of an accident of cell division
sex linked gene
a gene located on either sex chromosome. most occur on the x chromosome and show distinct patterns of inheritance
autosome
a chromosome that is not directly involved in determining sex; not a sex chromosome
codominance
the situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways.
incomplete dominance
the situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele
epistasis
a type of gene interaction in which the phenotypic expression of one gene alters that of another independently inherited gene
multiple alleles
more than 2 alleles controlling one trait and therefore more than a simple dominant/recessive relationship between alleles (blood types)
how do environmental factors affect phenotypes
environmental cues give to rise to modifications in phenotypes. They change the phenotypes in species to help them adapt, natural selection
linked genes
genes located close enough together on a chromosome that they tend to be inherited together
null hypothesis
there is no significant difference between the observed and expected frequencies
autosomal dominant
a pedigree where the dark color represents traits on the body that are common
autosomal recessive
a pedigree where the dark color represents traits on the body that are not common
sex linked dominant
a pedigree where the dark color represents traits on the X chromosome that are common (if the dad has it then all daughters have it)
sex linked recessive
a pedigree where the dark color represents traits on the X chromosome that are uncommon (if a daughter has it then the dad HAS to have it)
