Genetics: Chromosomes, Meiosis and Mitosis, and Inheritance Patterns

MCAT Basics (from MedSchoolCoach)

In this episode, we cover the foundational concepts of genetics, focusing on chromosomes, mitosis, meiosis, and inheritance patterns—important topics for the MCAT Bio/Biochem section. We’ll discuss how Gregor Mendel’s laws of segregation, independent assortment, and dominance influence inheritance and how Charles Darwin’s theory of natural selection relates to modern genetics.

The episode includes an overview of chromosome structure, the differences between X and Y chromosomes, and the effects of chromosomal mutations like deletions, duplications, and translocations. Mitosis and meiosis are also explained, with an emphasis on their roles in cell division and genetic diversity. Additionally, we explore genetic concepts such as codominance, incomplete dominance, genetic leakage, and how factors like penetrance and expressivity influence gene expression.

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Jump into the conversation:

(00:00) Introduction to Genetics and Chromosomes

(01:41) Background on genetics: Key figures and their contributions (Mendel, Darwin)

(03:37) Mendel’s Laws: Segregation, independent assortment, and dominance

(05:50) Charles Darwin: Evolution and natural selection in genetics

(09:43) Chromosomes and DNA: Discovery and role in inheritance

(11:29) Chromosome Numbers and Structure: Ploidy, chromatids, and human chromosomes

(14:06) X and Y Chromosomes: Sex determination and sex-linked traits

(18:34) Chromosomal Mutations: Duplication, deletion, inversion, translocation

(22:00) Mitosis: Stages and the production of identical daughter cells

(28:16) Meiosis: Gamete formation and genetic diversity

(32:40) Centrosome, Centromere, and Centriole: Roles in cell division

(33:50) Genes and Phenotypes: Alleles, genotypes, and their effect on traits

(38:28) Dominant and Recessive Alleles: How traits are determined

(40:37) Genetic Leakage, Penetrance, and Expressivity: Gene flow, expression likelihood, and variability

(42:47) MCAT Advice of the Day