Genetics Vocabulary Flashcards
Genetics
The study of how traits are inherited and passed from one generation to another.
Genes
A unit of heredity that can be passed down from a parent to their offspring.
Self vs. Cross-pollination
Self=fertilizing one plant with its own pollen; cross=fertilizing one plant with a different plant’s pollen.
Dominant vs. recessive
Dominant means that it only takes one inherited gene from one parent to show up. Recessive means that it needs to inherit both genes to be present.
Homozygous/purebred
Two of the same genes being passed down through several generations to keep it the same. Ex: RR or rr.
Heterozygous/hybrid
Inheriting both the dominant and nondominant gene. Ex: Rr.
Allele
Alternate versions of a gene.
Genotype
Genotype refers to your genetic makeup, or your combination of chromosomes. The three kinds are homozygous recessive (rr), homozygous dominant (RR), and heterozygous (Rr).
Phenotype
The genetic traits/genes that are actually physically expressed by the offspring.
Monohybrid cross
Crossing two versions of the SAME gene, one from each parent, such as crossing Rr and rr for tongue rolling.
Dihybrid cross
Crossing two different traits from each parent, such as crossing CCRr and Ccrr for hair color and tongue rolling.
Sex-linked traits
The gene is located on the sex chromosome.
Pedigree
A chart that traces the inheritance of a genetic trait within a family.
Polygenic trait
Two or more genes coding for a trait, like in eye color, hair color, IQ, and skin color.
Multiple alleles
Three or more alleles per gene.
Rh disease
When the father has positive blood, and the mother has negative blood, the baby’s blood could be positive. The mom’s body will make antibodies to the baby’s blood after birth, preventing her from having another baby.
Rhogam
The medicine used to treat Rh disease.
Sex-influenced trait
A gene that is found on the autosome, and its expression is influenced by sex hormones.
Fraternal vs. identical twins
Fraternal twins are dizygotic, meaning that there were two eggs and two sperm, equalling two separate zygotes. Identical twins are monozygotic, meaning that the fertilized egg separates into two cells.
Chromosome Map
A diagram that shows the location of a specific allele on a chromosome.
Gene linkage
When two genes are so close together on a chromosome that they are almost always inherited together because they do not separate during crossing over. Ex: blond hair and blue eyes.
Test cross
Crossing the parent with the unknown gene with the parent with the recessive gene and observing the offspring to figure out the genotypes.
Codominance
Both genes are expressed equally and fully. Ex: crossing a white flower with a red one and getting offspring with spots of red and white.
Incomplete dominance
When the offspring’s gene is an intermediate expression of both the parents’ genes, and neither is dominant. Ex; Crossing a red flower with a white one and getting a pink flower.
Chromosomal deletion
The loss of DNA from a chromosome, often resulting in genetic defects.
Chromosomal addition
Extra DNA is added to a chromosome.
Chromosomal translocation
The movement of DNA from one chromosome to another, often when non-homologous chromosomes pair up for crossing over.
Nondisjunction
Failure of chromosomes to separate properly during meiosis, leaving some cells with irregular numbers of chromosomes. (Ex: monosomy and trisomy.)
Monosomy
A nondosjunction resulting in the offspring having only one gene of the pair. Ex: Turner’s syndrome.
Trisomy
A nondisjunction resulting in the offspring having an extra chromosome. Ex: Down Syndrome
Down’s Syndrome
AKA Trisomy 21, there are 3 copies of chromosome 21 instead of 2, leading to developmental and intellectual delays.
Klienfelter’s Syndrome
When nondisjunction happens in the sex chromosomes, males can develop breasts and be infertile, although they are biologically male.
Turner’s Syndrome
A monosomy due to nondisjunction in which a female is missing an X chromosome, and is therefore infertile.
Karyotype
A picture of all of an individual’s chromosomes.
Chorionic Villi testing
At 8-10 weeks pregnant, the doctor can use sonar and a flexible needle to remove fetal chorion cells. This can be dangerous, but it allows for karyotyping.
Chorionic Villi testing
At 8-10 weeks pregnant, the doctor can use sonar and a flexible needle to remove fetal chorion cells. This can be dangerous, but it allows for karyotyping.
Endoscopy/fetoscopy
It involves using a camera and an endoscope that is inserted directly into the organ. It can help detect hydrocephalus.
