Unit 5 Vocab - Heredity Flashcards
Meiosis
a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (the sex cells, or egg and sperm)
Somatic cells (autosomes)
the cells in the body other than sperm and egg cells
Alleles
matching genes; one from our biological mother, one from our biological father
Gametes
a reproductive cell of an animal or plant
Haploid
the presence of a single set of chromosomes in an organism’s cells.
Nondisjunction
the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes
Diploid
the presence of two complete sets of chromosomes in an organism’s cells, with each parent contributing a chromosome to each pair
Germ cell
a progenitor cell that culminates in a gamete, or the sexual reproductive cell at any stage from the primordial cell to the mature gamete
Crossing-over
the exchange of DNA between paired homologous chromosomes (one from each parent) that occurs during the development of egg and sperm cells (meiosis)
Polar body
a cell that separates from the immature ovum during meiosis and that contains a nucleus produced in the first or second division of meiosis but very little cytoplasm
Genotype
the genetic makeup of an organism
Phenotype
an individual’s observable traits
Sexual Reproduction
Each parent contributes a gamete - a sex cell that has half of the normal DNA of a regular body cell
Homologous chromosomes
one of a pair of chromosomes with the same gene sequence, loci, chromosomal length, and centromere location
Karyotype
an individual’s complete set of chromosomes.
Recombination
the process by which DNA strands are broken and repaired, producing new combinations of alleles
Zygote
fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete (sperm)
Dominant allele
produces a dominant phenotype in individuals who have one copy of the allele, which can come from just one parent.
Recessive allele
A type of allele that when present on its own will not affect the individual.
Monohybrid cross
a breeding experiment in which the parents differ in only one genetically determined trait.
Dihybrid cross
a mating experiment between two organisms that are identically hybrid for two traits.
Law of segregation
only one of the two gene copies present in an organism is distributed to each gamete (egg or sperm cell) that it makes, and the allocation of the gene copies is random.
Homozygous
having inherited the same versions (alleles) of a genomic marker from each biological parent
Heterozygous
having inherited different versions (alleles) of a genomic marker from each biological parent
Probability
a measure of the likelihood of a statement or a theoretical expectation is correct
Incomplete Dominance
a form of Gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype
Codominance
a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual
Law of Independence Assortment
genes do not influence each other with regard to the sorting of alleles into gametes
Pedigree
a genetic representation of a family tree that diagrams the inheritance of a trait or disease though several generations.
Epistasis
a phenomenon in genetics in which the effect of a gene mutation is dependent on the presence or absence of mutations in one or more other genes,
Sex-linked Genes
characteristics (or traits) that are influenced by genes carried on the sex chromosomes
Linked genes
genes carried on the same chromosome
Test cross
a way to explore the genotpye of an organism.
Multiple allele inheritance
When there is a gene existing in more than two allelic forms
Pleiotropy
the phenomenon in which a single locus affects two or more apparently unrelated phenotypic traits
Chromosomal Inheritance
genes are found at specific locations on chromosomes,
Barr Body
the inactive X-chromosome in the somatic cells of mammalian females
Deletion
changes the DNA sequence by removing at least one nucleotide in a gene.
Dupiication
a type of mutation in which one or more copies of a DNA segment (which can be as small as a few bases or as large as a major chromosomal region) is produced
Translocation
occurs when a chromosome breaks and the (typically two) fragmented pieces re-attach to different chromosomes
