Genetics Review: Mendelian Inheritance & Central Dogma

Flashcards cover Central Dogma, transcription factors, autosomal inheritance (dominant and recessive), monohybrid and dihybrid crosses, Mendel's laws, and practice problems from the notes.

What does the Central Dogma describe in terms of molecular flow of genetic information?

DNA -> RNA -> protein.

What is the role of a trans-acting transcription factor?

A protein that binds DNA at regulatory regions to control when, where, and how much a gene is transcribed.

What is a cis-regulatory element?

A DNA sequence near a gene that transcription factors bind to regulate transcription.

What are Mendelian Traits?

Variation in alleles at a single genomic locus corresponds to variation of a single phenotypic trait.

On which chromosomes are human autosomal traits located?

Non-sex chromosomes, chromosomes 1 through 22.

What are the two main autosomal inheritance patterns?

Autosomal dominant and autosomal recessive.

In autosomal dominant inheritance, which genotypes express the phenotype?

Homozygous dominant (AA) and heterozygous (Aa) express the phenotype; homozygous recessive (aa) does not.

Why can two gain-of-function alleles be embryonically lethal in autosomal dominant diseases?

Two GOF alleles (homozygous dominant) can cause lethal effects during embryonic development.

Do autosomal dominant traits typically skip generations?

No; affected individuals can pass the trait to offspring of both sexes in successive generations.

In autosomal recessive inheritance, which genotype expresses the phenotype?

Two loss-of-function alleles (aa) express the phenotype.

Are males and females equally affected in autosomal recessive traits?

Yes; males and females are equally affected.

What is a carrier in autosomal recessive inheritance?

A heterozygous individual (Aa) with one normal and one LOF allele who typically has a normal phenotype.

Which genotype expresses autosomal recessive traits?

aa.

What is the F1 phenotype when crossing Tall (dominant) × Short (recessive) in a monohybrid cross?

All offspring are tall.

What is the F2 genotype ratio from a TT × tt cross?

1 TT : 2 Tt : 1 tt.

What is the F2 phenotype ratio from a TT × tt cross?

3 tall : 1 short.

What does Mendel's Law of Segregation state about alleles for a gene?

Alleles segregate into gametes; offspring inherit one allele from each parent.

What gametes are produced by an F1 individual that is heterozygous (Tt) in a monohybrid cross?

T and t.

What does Mendel's Law of Independent Assortment state?

Genes on different chromosomes assort independently, producing all possible allele combinations.

In a dihybrid cross with coupling TB / tb, which gametes are parental and which are recombinant?

Parental: TB and tb; Recombinant: Tb and tB.

What is the probability that a live-born puppy from two hairless dogs (autosomal dominant with HH lethal) will be hairless?

2/3.

If two phenotypically normal parents have a child with cystic fibrosis, what is the probability the next child will not have the disease?

3/4.

In a cross AaBb × AaBb (no linkage), what is the proportion of offspring with genotype aabb?

1/16.

What does LOF stand for and what does it mean?

Loss-of-function allele; reduces or abolishes function of the gene product.