genetic methods Flashcards
(30 cards)
What is genetic research?
The study of heredity—how traits are passed from generation to generation.
Who is considered the first geneticist?
Gregor Mendel, who discovered dominant and recessive traits through pea plant experiments.
What is a genotype?
The genetic makeup of an organism.
What is a phenotype?
The observable characteristics of an organism.
What is an allele?
A different version of a gene; can be dominant or recessive.
What does the Law of Segregation state?
Each organism carries two alleles per gene, which segregate during gamete formation.
What does the Law of Independent Assortment state?
Genes for different traits are passed independently of one another.
What is DNA?
A double helix made of nucleotide bases that contains genetic instructions.
What are chromatids?
Loose strands of DNA in a cell’s nucleus.
What are chromosomes?
Coiled chromatids formed during cell division.
What is a genome?
The entire set of an organism’s genes.
What are genes?
Sections of DNA that code for proteins.
What is a pleiotropic trait?
A trait affected by a single gene.
What is a polygenic trait?
A trait influenced by multiple genes.
Why are X-linked traits more common in males?
Males have only one X chromosome, so recessive traits on it are more likely to be expressed.
Name a disorder caused by X-linked inheritance.
Colour blindness, Turner Syndrome, Klinefelter Syndrome, or Fragile X Syndrome.
What are some key features of Turner Syndrome?
Affects females; X chromosome partially missing; includes physical and cognitive effects.
What are some key features of Klinefelter Syndrome?
Affects males; XXY genotype; includes learning difficulties.
What are some key features of Fragile X Syndrome?
Caused by repeats on FMR1 gene; associated with learning and behavioral difficulties.
What is Down’s Syndrome caused by?
Trisomy 21 – an extra copy of chromosome 21; leads to physical and cognitive symptoms.
What is Williams Syndrome caused by?
Microdeletion on chromosome 7 affecting about 25 genes.
What is the genetic basis of schizophrenia?
Schizophrenia is polygenic and influenced by environment.
What do twin studies help researchers understand?
They compare monozygotic and dizygotic twins to understand genetic vs. environmental influences.
What ethical issues are associated with early twin studies?
Peter Neubauer’s twin study was sealed until the 60s and considered unethical.
