Chapter 3: Principles of Genetics

Who formed the foundational work on genetics?

gregor mendel

What did Mendel's experiment show?

how traits are passed down from one generation to the next

What did Mendel's P1 generation show?

parent generation

What happened when Mendel crossed yellow and green peas?

1:2:1 genotype 3:1 phenotype

What is Mendel's Law of Segregation?

traits separate during reproduction into gametes and can reappear in offspring

What is a punnett square?

tools used in biotech to predict inheritance patterns of traits, including genetic disorders

How are punnett squares used in biotechnology?

traits separate during reproduction and can reappear

What is the Law of Independent Assortment?

Inheritance of one trait doesn’t affect the other

Why is the Law of Independent Assortment important in biotechnology?

Understanding how traits and genetic disorders are inherited independently

What is a testcross?

A tool to determine whether an individual showing a dominant trait is homozygous or heterozygous

What is homozygous?

same allele

What is heterozygous?

different alleles

Why are testcrosses important in biotechnology?

Identify carriers of genetic traits and predict the inheritance of disease

What is incomplete dominance?

shows how traits blend when no single allele is completely dominant

What does incomplete dominance show in biotechnology?

How genetic variation creates intermediate phenotype is important for plant breeding, medicine, and biotech

What is codominance?

two alleles are dominant together and pair together

What is an example of a trait determined by codominance?

blood types

Why is codominance important in biotechnology?

medicine, transfusions, paternity testing

What is polygenic inheritance?

Some traits are controlled by many genes working together

What is a classic example of polygenic inheritance?

skin color, weight, height

What type of results does polygenic inheritance produce?

form a range or gradient of phenotypes instead of just two possibilities

How is sex determined?

combination of sex chromosomes x and y

Why is sex determination important in biotechnology?

prenatal testing

How are sex linked traits determined?

controlled by genes on x chromosome

Why are males more likely to express X-linked disorders?

only have one x

How do females express sex linked disorders?

can carry traits without showing symptoms

Why is it important to understand sex-linked inheritance in biotechnology?

genetic disorders

What are chromosomal alterations?

large-scale changes in the structure of chromosome including entire segments of dna

What is deletion?

one segment of gene is missing. can cause sever disorders or developmental failures

What is inversion?

reorder genes. can cause cancer

What is translocation?

Two chromosomes switch segments. can lead to leukemia and infertility

What is duplication?

segments appear twice. can cause disease but also drive evolution.

What is crossing over?

process that increases genetic diversity through meiosis by exchanging DNA between homologous chromosomes and producing unique gametes.

Why is crossing over important in science and biotechnology?

variability in populations, evolution, and selective breeding

When does crossing over occur?

when same homologous chromosomes

What is nondisjunction?

failure of chromosomes to separate properly during meiosis

What is the result of nondisjunction?

too many or too few chromosomes

What diseases does nondisjunction help explain?

downs syndrome, turner syndrome, klinefelter syndrome

What is Down's syndrome?

extra chromosomes (trisomy)

What is Turner syndrome?

missing chromosome x in females

What is Klinfelter syndrome?

extra x in males